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Japanese Digital Television Project: An informed choice?

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Map of Digitisation of Television World wide

by Shanthilal Nanayakkara

Retired Principal Engineer, Digital Transition Division, Australian Communications and Media Authority

A Japanese delegation recently announced the resumption of the previously stalled digital television project in Sri Lanka following a meeting with the newly-elected President Anura Kumara Dissanayake. The commencement of the digitisation project is now imminent.

Once terrestrial television transmissions are digitised in Sri Lanka, it will replace the old analogue terrestrial television forever. Therefore, it is critically important that the final outcome is better than the current analogue television, if not far superior. Setting such a goal prior to the implementation of the project is crucial for its fruitful completion.

To achieve this outcome, deficiencies in the current parameters in the Japanese Digital Plans need to be revisited and appropriately addressed for the benefit of all stakeholders. Otherwise, as it stands today, there is a high potential for rural and regional viewers in Sri Lanka to miss out on the digital coverage. (This is further illustrated below). Such an unwarranted outcome could become a highly ‘politically sensitive’ issue for the new government .

Why Digital

In analogue transmissions, radio waves encounter several problems. When radio waves are subjected to multipath, ghosting images appear on television screen. They are also subjected to cancellation of their own signals and interference.

Digital technology overcomes these analogue transmission weaknesses and, as a huge value addition, is able to carry more information than its analogue counterpart. As this capacity enhancement feature helps carry multiple programmes on one frequency or channel, digital television transmission technology is considered to be highly spectrum productive. Once analogue is switched off, the vacant spectrum that can be harnessed, commonly known as Digital Dividend (DD), becomes an income earner for the Government, as spare spectrum can be sold to Telcos for broadband internet use. Thus, this digitisation project is effectively a self-financing venture for the government and a win-win for all stakeholders.

Stakeholder benefits of digital

Many countries in the world have now moved or are in the process of moving to the digital domain.

Irrespective of the digital television transmission standard adopted in Sri Lanka, benefits of a conversion from analogue to digital television are many for the majority of stakeholders.

These are listed below against the various stakeholders:

*  Government – a significant income from selling the vacant spare spectrum to Telcos, following full conversion to digital, provided appropriate modifications are made to the JICA plan;

*  Broadcasters – increased television channels and scope for increase of advertising revenue;

*  Viewers – increased number of television channels to facilitate a wider selection of content, with True High Definition (True HD) quality and potential 5.1 Surround Sound;

*  Content providers – opportunity to produce a wide range of programmes that are in demand;

*  Production houses – larger revenue from vastly increased niche productions;

*  Creators of social media and other internet-based content – opportunities to develop novel visual and aural media content;

*  Electronic Manufacturing/Testing – opportunities to manufacture digital television receivers and set up a receiver harmonisation/compatibility centre;

*  Broadcast Towers (similar to Lotus Tower) – Opportunities to establish and operate consolidated broadcast towers in the country;

*  Telcos- opportunity to purchase superior vacant spectrum for future fixed and mobile broadband applications.

Funding arrangements or self-financing

The current funding arrangement for digitisation of television in Sri Lanka is a ‘soft loan’ from the Japanese government, and it is tied up in ‘one bundle’ with loans for other projects. This loan is also based on the premise that the deployment of the Japanese digital television standard, Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) is mandatory. As the vacant spectrum can be sold after Analogue Switch Off (ASO), the venture could also be a self-financing project, albeit with bridging finance.

Purpose of this essay

The main purpose of this article is to suggest ways of optimising the benefits of the digitisation project while retaining the support of the Japanese government. If the bulk of problems for viewers and broadcasters can be removed by making appropriate adjustments to the current plans at a minimal cost, with broadcasters becoming willing participants, the digitisation of television in Sri Lanka would no doubt be a success for all stakeholders, including the new government. Otherwise, there is an urgent need to review the bi-lateral agreement that was signed previously.

The broadcasting fraternity in Sri Lanka is fully aware that the Japanese system is not as efficient as the second generation European standard, Digital Video Broadcast-Terrestrial 2 (DVB-T2).

Understanding Digital

Simply put, digitisation of analogue vision and sound enables radio waves to carry more information within the same channel or bandwidth than in the analogue era. This allows producers of visual and aural content to be more creative than before. The technology also facilitates easy communication in both fixed and mobile environments and facilitates two-way communication more than in the analogue era. However, there are two main pitfalls that one needs to address in order to make the venture a success. They are as follows:

Cliff effect (sudden loss of signal): –

* to avoid the ‘cliff effect’ a robust signal (with higher reliability and availability at a receive location than in analogue era) is needed at the receiver to prevent momentary picture pixelation and/or sudden loss of signal; and

* it is also necessary to ensure that all television digital services reaching viewer locations are of the same signal strength to ensure equity of services and therefore must originate from ONE location such as the Lotus Tower.

* Absence of ‘graceful degradation’ and its effect on signal level – even with a degraded signal with ‘snowy pictures’, analogue signal is still watchable. It is not so with digital due to ‘cliff effect’. Therefore, there is a need to ensure that the digital coverage is the same or better than the existing watchable analogue coverage that is defined by a signal level of 43 dBuV/m in VHF Band III.

This limit was adopted for digitisation in Australia.

Deficiencies of the Japanese standard/plan

In planning to deploy the ISDB-T system in our country, everyone should aim for a cost-beneficial outcome as it is of paramount importance to all stakeholders. There are several issues in the Japanese documentation of 2014/2018, which should be addressed to suit the needs of the public/consumers, broadcasters and government. They range from policy issues at the outset, technical areas during planning and management issues during the proposed phases of ASO and Digital Switch On (DSO).

Spectrum for Digital: VHF/UHF issue

In particular, the proposal to use only a part of the available broadcast spectrum has an impact on the eventual DD income for the Government. The Japanese have deployed both VHF and UHF spectrum in Brazil, strangely not offered to Sri Lanka. In that context, it is not clear why the Japanese team has not proposed a VHF and UHF combined solution as deployed in Brazil. This was pointed out by the writer when a Japanese team, including a senior Embassy official Sato Takefumi, met him in 2017 in Colombo to discuss Lotus Tower issues (after his disclosure in an article in The Island about the Lotus tower) and digitisation in general. Their response was ‘no one asked for it’.

As it stands today in Sri Lanka, analogue television transmissions are based on frequencies using both VHF and UHF Bands, but the proposed Japanese digital conversion is not utilising the VHF Band. In particular, VHF Band III exhibits superior propagation characteristics, while contributing to lower the consumption of electricity by the transmitters. More importantly, VHF radio waves carry longer distances than UHF due to lower propagation losses, are able to travel around obstacles comparatively and therefore VHF is more suitable for wide coverage transmissions.

Currently, the VHF spectrum is occupied by three television broadcasting networks i.e. Rupavahini, ITN and TNL. These networks will lose their inherent wide coverage VHF Band advantage. They also have the additional burden of occupying a digital channel in the UHF spectrum, especially when the earmarked UHF channels for digital are almost at the bottom of the UHF Band V, where propagation losses are higher than in UHF Band IV.

ISDB-T New Coder H.265

It is a known fact that the Japanese ISDB-T standard, in payload capacity terms, is second to the second generation European Standard DVB-T2 that provides 45 Mb/s capacity. However, the Japanese standard can only carry about 1/2 of the European standard per channel at 23 Mb/s. But as the Japanese are now offering to change the content source coder to H.265, they will be able to provide HD at 1080P at a rate of 2-4 Mb/s. This change would now allow all HD TV ready broadcasters to provide True HD content at 1920 x 1080P and possibly can accommodate all television channels in Colombo. But the downside is that the receivers are going to be more complex with the new coder. This may then lead to more expensive ISDB-T receivers or STBs in Sri Lanka.

Vacant VHF Band III

The unused VHF Band III is likely to reduce the DD for the government though the Japanese strategy is to achieve some productivity by the use of single frequency networks in the UHF Band (SFNs-a technique to use the same frequency multiple times to improve spectrum productivity). However, in practice receiving of SFNs is not simplistic as the reception of SFN signals are subject to receiver complexities.

The Telecommunications Regulatory Commission (TRC) may be exclusively reserving the VHF band for future digital radio, but the same band could be co-shared with digital television without any problems. For example, Australia is co-sharing VHF Band III for both digital television and radio without any issues.

Once all analogue transmissions are switched off with the deployment of UHF band per se for digital, the unused VHF Band III spectrum, where 7 MHz bandwidth, 8 VHF Frequency channels exists, will become vacant.

This is clearly a waste of unused spectrum. Additionally, as Restacking [restack is the re-arrangement of frequencies ideally in the two bands of VHF and UHF, to maximise the spectrum productivity] is in the Japanese Plan, additional expenditure on broadcasting infrastructure is also on the cards. Where are the funds coming from?

There is no mention of new funding arrangements for Restacking of the spectrum, and it also raises questions about the STB/Receiver specifications as frequencies may need to change after Restacking.

If some broadcasters are not keen to use ISDB-T, they may canvass for the opportunity to use the vacant VHF Band for the potential deployment of DVB-T2 standard. This MUST be avoided at all costs! If this happens, there will be two digital systems in Sri Lanka. This issue, in particular, could become another potential headache for the government as it is likely to be under heavy pressure from commercial broadcasters to release the vacant VHF Band III for the more efficient DVB-T2. This issue, too, was pointed out by the writer when another Japanese team consisting of a Senior Engineer from Yacheo Engineering along with Sato Takefumi of the Japanese Embassy met him in 2017/2018.

Unless there are plans to use the vacant VHF Band III by Restacking the spectrum, this spectrum specifically allocated for broadcasting would go to waste.

Digital Signal Reliability & Availability

Unlike in the analogue domain, television signal reliability and its availability becomes crucial in digital reception. In the analogue era, television broadcasting service field strength was planned for 50% of the locations and 50% of the time at a receiving height of 10 m. But in digital this becomes 80%-95% of the locations and 90% of the time to ensure reliability and availability of the digital signal. Hence the planned field strength would need to be adjusted to ensure the required reliability and availability at a higher field strength. In Australia, field strength used was 50 dBuV/m for Band IV and 54 dBuV/m for Band V frequencies in a rural environment

However, it is not clear from the published documents of the Japanese plans 2014/2018 whether this issue had been addressed or otherwise. The signal level at 51 dBuV/m identified in the 2018 Japanese documentation is certainly not adequate for a rural grade of service in the UHF Band! It ought to be in the region of 54-74 dBuV/m in the UHF Band V. For example, the Australian Broadcasting Planning Handbook for Digital Television Broadcasting has clearly identified these requirements and provided information on how they were derived.

Duplication Parameter

The potential impact of the proposals for duplication of coverage is illustrated in the diagram. (See Figure 01)

The signal threshold of a planned analogue coverage is 50 dBuV/m for VHF Band III. However, some regional and rural viewers in Sri Lanka are currently receiving watchable analogue signals well below this value. If, as planned by the Japanese studies in 2014, the analogue coverage is converted at the planned cut-off level of 55 dBuV/m, then the majority of regional and rural viewers, who are currently watching the analogue television with no issues, will not be able to receive digital television coverage. This could potentially become a political nightmare for the new government. Therefore, the cut-off signal level, as illustrated above, should be lowered to 43 dBuV/m.

Though Single Frequency Networks (SFNs) are a solution to mitigate this difference in coverage, it is not easy to implement them at the receiver-end due to the variation in receiver profiles of Set-Top-Boxes (STBs) and complexities in receiver SFN signal detection.

The Japanese designers, while being aware of this issue, may have been heavily constrained due to the requirement for spectrum productivity. Most probably, given the limits of the available UHF spectrum for digital and the lower data efficacy of the Japanese ISDB-T standard, this higher limit of duplication may have been proposed by the designers in order to preserve some spectrum productivity.

One Network Operator for Digital

The advent of digital terrestrial television also signifies the end of individual transmission facilities for broadcasters, as several content feeds are carried on one frequency or the channel and the requirement to consolidate all transmissions at one site. A combined digital transmission service provider may, in the future, be an independent entity and the facilities may be offered to the broadcasters on a fee-levying basis, based on a pragmatic business plan. In a future digital broadcasting landscape, the broadcasters will essentially be ‘content’ providers. Perhaps, there ought to be some sort of protection provided to the existing broadcasters in the event new content providers also express a desire to use digital transmissions.

Cost to viewers and broadcasters

All consumer television sets require digital receivers to extract video and audio content from digital transmissions. Therefore, either in-built ISDB-T receivers or compatible STBs are required. For example, there are flat TVs that do not have in-built ISDB-T receivers. The cost of an STB for ISDB-T with H.265 decoders, is likely to be around US $ 50-100, depending on their complexity and economies of scale. If in the event, there is likely to be a Restack of frequencies including the VHF Band, two band STBs or receivers may be needed; one during the first phase and another after the Restack of channels with the ability to tune into the VHF Band. Additionally, at some household locations, there may also be a requirement for new receiver antenna installation to receive VHF/UHF channels. If so, this is also an additional cost to the viewer.

There is also a significant cost to the commercial television broadcasters to provide HD ready studios, Outside Broadcast (OB)/Electronic News Gathering (ENG) equipment, and content feeding arrangements. However, once the commercial television broadcasters elect to use consolidated broadcast towers, analogue era transmission costs would also disappear as their independent transmission networks are no longer needed, in a digital environment. It is noteworthy to highlight that the Japanese financial proposal for digitisation of television is primarily for Rupavahini, and limited to funding the analogue to digital transfer of Rupavahini facilities, including the provision of a True HD studio, OB unit, Transmission equipment and a Central Command centre for the proposed Digital Broadcast Network Operations (DBNO) at the Lotus Tower.

At this stage, there are no signs of any discussions with the broadcasters to develop a ‘road map’ to facilitate the smooth transition from analogue to digital of commercial channels. If Restack is to take place, there is likely to be additional costs but there is no mention of further Japanese funding for Restack of channels either.

As additional costs to the commercial television broadcasters are likely, strategic government policy initiatives to compensate for the additional capital expenditure in a highly competitive market are in order.

Way forward

It is heartening to note that the Japanese plan has now incorporated the more efficient coder in H.265 with an intention to maximise the use of limited payload capacity of an ISDB-T channel, which then will result in providing True HD transmission (1920 x 1080P) for ALL licensed television channels in Colombo.

If Japanese consultants can pay attention to the issues of using VHF Band III, changing receiving the field strength requirements to that of the ITU signal level requirements for UHF and address the duplication parameter issue, then ALL stakeholders including the government and broadcasters will no doubt look forward to the venture of digitisation of television in Sri Lanka.



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Features

A new mediation law for smarter dispute resolution of civil and commercial disputes – II

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(Part I of this article appeared in The Island yesterday.)

An examination of how some of the other countries have institutionalised mediation to address the problem of laws delays shows that an array of institutional devices have been adopted to provide for mediation not only as a voluntary option but also in some jurisdictions, as a mandatory requirement prior to litigation, to respond to serious issues of delays due to congestion in courts.

In the UK , in March 1994, the Lord Chancellor commissioned Lord  Woolf to review the Rules of civil procedure with a view to improving access to Justice, reducing the cost of litigation and removing unnecessary complexity. The resulting  Access to Justice Report (1996) triggered a series of reforms to improve the civil justice system primarily through the civil procedure rules (1999) which articulated that its overriding objective is to enable the court to deal with cases justly and at proportionate cost. In 2023, the Court of Appeal judgment in Churchill v. Merthyr Tydfil County Borough Council [2023] EWCA Civ  1416, decided that English courts do have the power to stay civil proceedings for, or order, parties to engage in mediation or another non-court- based dispute resolution process. The Rules were thereafter amended in 2024 to provide for the use of alternative dispute resolution (ADR) more proactively. These included rules that recognied that –

* promoting  or using ADR is a means of achieving the overriding objective;

*  the court has a duty to actively manage cases to further the overriding objective, including by ‘ordering or encouraging the parties to use, and facilitating the use of, alternative dispute resolution’ and ‘helping the parties to settle the whole or part of the case’

* in deciding a costs order, a court will have regard to all the circumstances of the case, including the conduct of the parties, including whether a party failed to comply with an order for ADR or unreasonably failed to engage in ADR.

An ADR pledge made by the UK Government in 2001 was renewed in 2011, by the Dispute Resolution Commitment (DRC) requiring departments to use mediation, arbitration and conciliation. At that time, the then Justice Minister Jonathan Djanogly said: ‘I believe that government should be leading by example by resolving issues away from court using alternatives which are usually quicker, cheaper and provide better outcomes. We want people to see court as a last resort rather than a first option, and cut down on the amount of unnecessary, expensive, painful and confrontational litigation in our society. In many cases methods like mediation are simply a common sense solution which benefits everyone involved. Although they will not be suitable in every case, they are already saving taxpayers millions every year and can save much more.’

The judicial dicta on the power of the courts to order mediation and the imposition of costs on even a successful party for unreasonable refusal to mediate, provides clear acceptance of a pro mediation approach by the UK courts.

In the USA , the discussion on the need for alternatives was raised in a speech made in 1906, by Roscoe Pound, a relatively unknown legal academic at the time, addressing the annual meeting of the American Bar Association (ABA). The title of his address was “The Causes of Popular Dissatisfaction with the Administration of Justice.”  He critiqued the American legal system and charged that it was riddled with archaic technicalities, too slow, too expensive and adversarial and that there was injustice when  procedure received emphasis above the substantive issues of a conflict. He spoke of the “sporting theory of justice” where litigation was considered as a game where the lawyers were gladiators battling in court to win. He charged that the contentious procedure compels ‘counsel to forget that they are officers of the court and  to deal with the rules of law and procedure exactly as the professional football coach with the rules of the court.’ At the time, Pound’s criticisms were considered scandalous, blasphemous and the ABA refused to publish the speech.  Things changed however.

Thirty years later, Roscoe Pound went on to become Dean of the Harvard Law School and became  a celebrated legal luminary. As for the legal system – Roscoe Pounds sentiments were not dismissed. Seventy years later in 1976, the then Chief Justice Warren Burger convened the Pound Conference (called the second  Pound Conference, with the first attributed to Pounds’ 1906 speech event), to consider whether Pounds’ criticisms had been adequately addressed and what more needed to be done. Professor Frank Sander of the Harvard Law School delivered the keynote address and spoke of his vision for a comprehensive Justice center (the “multi door court house”) where an alternative system would function parallel to the litigation system and disputes would be directed to the most appropriate process, such as arbitration and mediation.

The impact of these discussions resulted in significant changes to the dispute resolution landscape in the USA through statutes, inclusion of ADR in academic courses, and the professionalization of the practice of ADR processes, including mediation. Currently, arbitration and mediation are recognized within the mainstream legal system with resounding success.  All the States have recognized ADR pathways including mediation, in statutes. Mediation is well entrenched in the USA and the success rate is reportedly very high.

Australia has institutionalized mediation through several statutory and other initiatives. Courts are empowered to refer disputes to mediation without the consent of the parties to enable better management of civil matters. The Civil Dispute Resolution Act,  2011 contains provisions to ensure that, other than in respect of certain excluded civil proceedings,  parties must take “genuine steps” to resolve disputes prior to litigation. The Act obligates parties instituting proceedings in court to file a “genuine steps statement” setting out the steps taken to resolve issues or the reasons why no such steps were taken and further provides that a Lawyer acting for such a party must advise that party of the requirement and assist that party to comply with that requirement.

In Ireland, in the very recent case of Burke v O’Connell  [2026] IEHC 314 (May 20, 2026), the High Court considered  whether a court can order parties to mediate a dispute, against their will, or whether a court is restricted to simply inviting the parties to mediate. Among other issues, the court considered whether mandatory court ordered mediation is a breach of a constitutional right of access to courts, and decided that a court delaying court proceedings for court ordered Mediation, even against the will of the parties, would not constitute a breach of the right access to the courts under the Constitution or the European Convention on Human Rights, and that judges in Ireland regularly make clear that the right of access to the courts is not unconditional. Importantly the court observed that the court is not directing the parties to reach an agreement but simply to commence  a mediation.  The Court also observed that a court directed mediation order is a very limited order which does not compel settlement and only requires parties to commence a Mediation process and that while attendance at Mediation may not be voluntary, reaching a settlement is voluntary and made order that a court, in controlling its own process, did have the power to direct Mediation in appropriate cases, and that it was an inherent power of the court to ensure the effective and efficient operation of the courts.

 The Indian Mediation Act, 2023  articulates a pro mediation policy and provides for mediation via a court annexed scheme for which detailed statutory provisions are included. The Act states that parties may voluntarily, and whether there is a mediation agreement or not, take steps to pursue court annexed pre litigation mediation and provides for the steps to be taken therefor (section 5). The Act provides further that, even if such pre litigation mediation is unsuccessful, a court or tribunal may, at any stage of the proceedings, refer parties to undertake mediation and that when a court so refers a dispute, there is no obligation on the parties to come to a settlement (section 7). In respect of high value commercial disputes however,  a plaintiff is required to exhaust ‘the remedy of  pre institution mediation’ prior to instituting action, unless urgent interim relief is sought – section 12A introduced by the Commercial Courts, Commercial Division, and Commercial Appellate Division of High Courts (Amendment) Act, No. 28 of 2018.

 In South Africa, parties are mandated to consider mediation before initiating  litigation in the High Court. Challenged by a serious issue of a severe backlog, with trial dates scheduled even up to 2031, a Directive was issued by the Judge President of the Gauteng Division of the High Court along with a detailed process Protocol, effective April 2025 to require mandatorily that prospective litigants in all civil matters within the Gauteng division must participate meaningfully in a court-annexed mediation process before they can be allocated a trial date. The protocol requires, among other documents, that a Report of the Mediator stating, among other matters, whether parties “participated in good faith” be filed, to obtain a trial date. This requirement has been included to avoid what the Judge President refers to as “sham mediations.”  (https://www.youtube.com/watch?v=v5Gmkzfu8gA&t=425s) Non-compliance results in matters being struck off the roll and could lead to adverse or punitive cost orders. Currently, a challenge to this Directive by the Personal Injury Plaintiff Lawyers Association and the Law Society of South Africa is pending, without a stay of the Rule.

 Singapore has emerged as a global leader in the practice of mediation. The Mediation Act 2017 provides for a framework for the use of mediation and for enforcement of a mediated settlement agreement as a decree  of court. Mediation is well entrenched in the legal system of Singapore and enjoys the support of government as well as the judiciary. Singapore played a key role in UNCITRAL in the deliberations that led to the drafting of the text for the 1998 UN  Mediation Convention and was host to the Convention signing ceremony in August 1999 where a historical number of 46 countries, including Sri Lanka, signed the Convention on the very first day. Many of the training programmes for Sri Lankans that have been arranged by the International ADR Center, have been conducted by the Singapore International Mediation Centre (SIMC) which is renowned for its programmes and for services to handle international commercial disputes.

 The European Union Directive (EU Directive 2008/52/EC) provides that a court may, when appropriate and having regard to all the circumstances of the case, invite parties to use mediation (Article 5.1) and that the Directive is without prejudice to national legislation to making the use of mediation compulsory or subjective to incentives or sanctions … provided that such legislation does not prevent the parties from exercising their right of access to the judicial system (Article 5.2). Many European countries have integrated mediation into their dispute resolution systems through legislation or procedural laws in ways that range from recognizing voluntary reference to mediation to requiring mandatory mediation for specified categories of disputes. Countries such as Italy, Greece, Germany and Belgium are some that have robust systems.

It is clear therefore, that jurisdictions around the world, irrespective of the legal system, have sought to recognize mediation for its value not only for minor community dispute resolution but also for the resolution of high value commercial and other family and civil dispute resolution.  UNCITRALs preparation of the text for the 1988 UN Mediation Convention was inspired by the significant increase in the use of mediation in international trade and the need for a uniform regime for enforcement, such as the UN NY Arbitration Convention provides in respect of arbitration awards.

 Sri Lanka’s advancements have thus far been driven by the private sector. A holistic approach to find responses to the backlog in courts to relieve the pressure on courts, is desired. The promotion  of ADR, including mediation, deserves support from the government as well, since, clearly, laws delays have an adverse impact on the economy of the country and should not be seen only as an access to justice issue. As articulated in the UN Mediation Convention, among the positive beneficial results of using mediation for dispute resolution, is that there are cost savings for the State. It is a means of resolving disputes without detracting from the quality of the resolution.

 

by Dhara Wijayatilake
Attorney at Law; Former Secretary to the Ministry of Justice; Director and Secretary General of the International ADR Center

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Killing of Colombo’s ancient trees — a warning on UN’s World Desertification Day – 17 June

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A fallen tree in Colombo. (File photo courtesy NewsFirst)

In recent years, falling trees have claimed lives, destroyed homes, and sparked an urgent debate: should Colombo’s ancient trees be cut down in the name of safety? But this is the wrong question. The real crisis is not that these trees are dangerous — it is that we have made them so. Through decades of road widening, root-smothering pavements, and indiscriminate branch cutting, we have steadily undermined the very trees we now fear. What we are witnessing is not nature failing us. It is us failing nature. As the world marks World Desertification Day on 17th June, Sri Lanka would do well to reflect that desertification does not begin only in distant, arid lands — it begins whenever a city turns its back on its own green heritage.

In recent years, falling trees have claimed lives, destroyed homes, and sparked an urgent debate: should Colombo’s ancient trees be cut down in the name of safety? But this is the wrong question. The real crisis is not that these trees are dangerous — it is that we have made them so. Through decades of road widening, root-smothering pavements, and indiscriminate branch cutting, we have steadily undermined the very trees we now fear. What we are witnessing is not nature failing us. It is us failing nature.

Colombo, our commercial capital, is considered one of the greenest cities in the world. This is highlighted by the award of the world’s first Wetland City designation to our administrative capital, Sri Jayewardenepura Kotte. Both cities and their green heritage should be treasured and protected — not only as assets of their citizens, but as a matter of national pride.

It is against this backdrop that one must view with deep concern the ongoing destruction of trees and greenery across Sri Lanka, particularly in urban settings such as Colombo and Kotte. The majestic trees lining our traditional tanks, rural areas, and urban areas are part of our heritage. The trees lining Colombo’s Ananda Coomaraswamy Mawatha (previously named the Green Path because of its large trees), Gregory’s Road, Thurstan Road, and Bauddhaloka Mawatha, are over a hundred years old. These are living monuments of our heritage. They provide shade, a natural canopy, and a habitat for a remarkable diversity of bird populations within the city. It is therefore vital that we make every effort to preserve these trees unless they pose a direct danger to human life.

Why Do These Trees Become Dangerous?

To address this question, we must first understand why large trees continue to fall during periods of strong winds. Old photographs indicate that it is we who have widened roads and built pavements to cover the roots of these majestic trees, a true heritage from the past.

A leading reason for trees to fall is age-related decay. Old trees tend to develop weak branches and trunks. Regular inspection of their structural integrity and timely treatment of disease would go a long way in preventing such failures.

The second reason is indiscriminate cutting of branches, which disrupts the natural balance of the tree. A principal offender in this regard is the Ceylon Electricity Board. When interviewing workers engaged in trimming city trees, one consistently hears the same justification: the branch must be cut because it is touching or close to a power line. There are no arborists, trained experts, or senior officials to guide these workers or determine whether a less destructive approach is possible.

The third reason is the destruction of root systems. Across the city, one can observe concrete and paving laid directly over the root zones of large trees. This prevents oxygenation and moisture from reaching the roots, causing them to deteriorate or die. The inevitable consequence is that the tree gradually loses its structural support at the base, making it vulnerable to falling.

What Should Municipalities and Town Councils Do?

To save our ancient trees, we must counter the flawed argument that we need to replace them—these trees are priceless “nature’s investments for hundreds of years” and, as a BBC article on ancient oaks suggests, their genetic heritage is vital for resilient future forests. See “1,000-year-old oaks used to create ‘super forest’ (See )

*  A nationwide strategy is essential: we must start by strengthening the expertise of tree officers in the Colombo Municipal Council and other urban councils to ensure professional health assessments are available, while also linking with botanists, academics, and environmental groups at the University of Colombo.

*  Use Google Maps and GIS for systematic mapping and reviving a citizen science platform, similar to one previously developed by University of Moratuwa, where students and the public can report environmental harm with photos and locations.

*  Technology offers more powerful tools. There are Conventional Visual Tree Risk Assessment (VTRA) methods which fail to detect risks. More advanced methods were reported at the 30 th International Forestry and Environment Symposium 2026 e.g. Ground Penetrating Radar (GPR). These are able to find trunk decay and found examples in urban trees at Viharamahadevi park and Keppetipola road.

*  We can raise public awareness through social media and community events like “tree walks,” a practice which could be further popularized by groups like Ruk Rakaganno (see ) and the Love A Tree Foundation (see )

*  Finally, we must learn from international models like the UK’s Ancient Tree Forum (see ). The latter specialises in protecting trees as a heritage which must be preserved and protected for future generations.

by Saroj Jayasinghe
Emeritus Professor
Consultant Physician

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Dengue and its prevention: A global public health challenge

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Dengue is one of the fastest spreading mosquito-borne viral diseases in the world today, posing a growing threat to nearly half of the global population. The World Health Organization describes dengue as a viral infection transmitted to humans through the bite of infected female mosquitoes, primarily Aedes aegypti and, to a lesser extent, Aedes albopictus. Once considered a disease limited to tropical regions, dengue has now expanded widely across continents, driven by urbanization, climate change, population movement, and weak vector control systems.

The global burden of dengue has increased dramatically over recent decades. According to WHO estimates, there are approximately 100 to 400 million infections annually, although a large proportion remain asymptomatic or undiagnosed. The disease is now endemic in over 100 countries, with Asia bearing the highest share of cases, followed by Latin America and Africa. As transmission intensifies and outbreaks become more frequent, dengue has emerged as a major public health concern requiring coordinated prevention and control strategies.

The nature of dengue infection

Dengue is caused by four closely related viruses known as serotypes: DENV-1, DENV-2, DENV-3, and DENV-4. Infection with one serotype provides lifelong immunity to that specific strain, but only partial and temporary protection against the others. This means a person can be infected up to four times in their lifetime.

Most dengue infections are asymptomatic or mild. When symptoms do occur, they typically appear 4 to 10 days after the bite of an infected mosquito. The clinical presentation includes high fever, severe headache, pain behind the eyes, muscle and joint pain, nausea, vomiting, rash, and fatigue. Because these symptoms resemble other viral infections, dengue is often underdiagnosed in early stages.

While most patients recover within one to two weeks, a small proportion develop severe dengue. This life-threatening condition is characterised by plasma leakage, severe bleeding, organ impairment, and shock. Without timely medical intervention, severe dengue can be fatal. WHO emphasises that early diagnosis and appropriate clinical management can reduce fatality rates to below 1 percent in well-managed settings.

Transmission and mosquito ecology

Dengue is transmitted primarily through the bite of infected female Aedes mosquitoes. These mosquitoes are highly adapted to urban environments and typically breed in artificial water containers found in and around homes. Unlike malaria-transmitting mosquitoes, Aedes mosquitoes bite during the daytime, with peak activity in the early morning and late afternoon.

The lifecycle of the mosquito plays a crucial role in transmission. Eggs can survive for months in dry conditions and hatch when they come into contact with water. Even small collections of water, such as flower pots, discarded containers, tyres, and water storage tanks, can serve as breeding sites.

Urbanisation has significantly contributed to the spread of dengue. Rapid population growth in cities often leads to overcrowding, poor waste management, and inadequate water storage practices, all of which create ideal breeding conditions for mosquitoes. Climate factors such as increased rainfall, humidity, and temperature further enhance mosquito survival and virus replication.

Risk factors and global expansion

Several factors increase the risk of dengue transmission. Population density is a key driver, as densely populated urban areas provide abundant human hosts for mosquitoes. Inadequate housing conditions and poor access to clean water force communities to store water in containers, which often become breeding grounds.

Human mobility also contributes to the spread of the disease, as infected individuals can introduce the virus into new regions where competent mosquito vectors are present. Climate change has expanded the geographical range of Aedes mosquitoes into previously unaffected areas, increasing the risk of outbreaks in both tropical and subtropical regions.

WHO has noted that dengue incidence has increased significantly over the past 50 years, with periodic outbreaks becoming more frequent and severe. The disease is now considered a major global health threat, comparable in burden to other high-impact infectious diseases in many regions.

Clinical management and absence of specific treatment

There is currently no specific antiviral treatment for dengue. Management is supportive and focuses on relieving symptoms and preventing complications. Paracetamol is recommended to reduce fever and pain, while non-steroidal anti-inflammatory drugs such as ibuprofen and aspirin are avoided due to their risk of increasing bleeding.

Patients with severe dengue require hospitalisation for close monitoring and supportive care, including intravenous fluid replacement and management of shock or bleeding. With proper medical care, mortality rates can be significantly reduced.

Early detection is critical. Warning signs such as persistent vomiting, severe abdominal pain, bleeding gums, rapid breathing, and sudden fatigue indicate progression to severe dengue and require immediate medical attention.

Prevention: the cornerstone of dengue control

Since there is no specific cure, prevention remains the most effective strategy against dengue. WHO strongly emphasises integrated vector management as the foundation of dengue control.

Personal protection measures are essential, especially during daytime hours when mosquitoes are most active. These include the use of mosquito repellents containing DEET, picaridin, or IR3535, wearing long-sleeved clothing, and using mosquito nets when resting during the day. Window and door screens also help reduce indoor mosquito exposure.

Environmental management is equally important. Communities are encouraged to eliminate breeding sites by removing stagnant water, disposing of waste properly, and cleaning water storage containers regularly. Even small water collections can sustain mosquito populations, making household-level participation crucial.

Public health programmes also rely on insecticide spraying during outbreaks to rapidly reduce mosquito populations. However, WHO emphasises that chemical control alone is insufficient without sustained community involvement and environmental management.

Community participation and public health response

Community engagement is a central pillar of dengue prevention. Effective control requires continuous participation from households, schools, workplaces, and local authorities. Public awareness campaigns play a vital role in educating populations about mosquito breeding habits and personal protection measures.

Surveillance systems are also essential for early outbreak detection and response. Health authorities monitor dengue cases and mosquito populations to identify high-risk areas and implement targeted interventions.

Integrated approaches that combine environmental management, biological control, chemical interventions, and public education have proven most effective in reducing transmission.

Vaccination and emerging tools

In recent years, dengue vaccines have been developed and introduced in some countries under specific conditions. WHO has recommended the use of certain vaccines in areas with high transmission, particularly for populations with prior exposure to dengue. However, vaccination strategies remain limited and must be carefully implemented due to the complexity of immune responses to dengue infection.

Research continues into new tools such as genetically modified mosquitoes, Wolbachia-infected mosquitoes that reduce virus transmission, and improved diagnostic technologies. These innovations offer promising additional tools but are not yet substitutes for established prevention measures.

Dengue remains a rapidly growing global health challenge with significant medical, social, and economic impacts. Its spread is driven by urbanisation, climate change, and the adaptability of mosquito vectors. While no specific cure exists, timely clinical care can prevent deaths, and effective prevention strategies can significantly reduce transmission.

The World Health Organization emphasises that dengue control depends on a combination of personal protection, environmental management, community participation, and strong public health systems. As the disease continues to expand geographically, sustained global commitment is essential to reduce its burden and protect vulnerable populations.

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