‘Tamil Nadu is designing systems that anticipate and adapt to environmental challenges, not just react to them’

Tamil Nadu is tackling its environmental, climate and biodiversity challenges with a series of new initiatives, including the launch of a climate company. Down To Earth’s Rohini Krishnamurthy sits down with Supriya Sahu, additional chief secretary of environment, climate change & forests, Tamil Nadu government, to discuss the unique issues facing the state. She also speaks about the progress made so far and the coastal state’s long-term vision for a sustainable future.

Rohini Krishnamurthy: What are some of the environmental challenges that are unique to Tamil Nadu, especially as a coastal state?

Supriya Sahu: Tamil Nadu faces a distinct set of environmental challenges, many of which are amplified by its long coastline and densely populated urban areas. Of our 38 districts, 14 are coastal and the state has a 1,069-kilometre-long coastline, the longest on the Indian mainland after Gujarat, making us particularly vulnerable to the impacts of climate change.

The most pressing issues include extreme weather events such as sudden and intense rainfall, the urban heat island effect, rising sea levels, coastal erosion and the increasing frequency and intensity of cyclones, all of which contribute to flooding in both urban and rural areas. Safeguarding the lives and livelihoods of our coastal communities, while minimising environmental degradation, remains a top priority.

Air pollution is another concern. Tamil Nadu has only four cities — Chennai, Madurai, Trichy and Thoothukudi — classified as non-attainment cities under the National Clean Air Programme. However, sustained interventions over the past four years have yielded measurable progress, particularly in Chennai and Trichy, where particulate matter levels have shown a steady decline. Contributing factors include large-scale urban greening initiatives under the Green Tamil Nadu Mission, improved dust suppression measures such as water and mist spraying and stricter controls on vehicular emissions. We are also in the process of developing a dedicated policy for urban greening to institutionalise and expand these efforts.

Another critical challenge is urban flooding, particularly in north Chennai. The government constituted a high-level expert group to study the underlying causes. This group analysed over a decade’s worth of data, examining flood patterns, land use, cyclonic trends and urban heat stress. Their recommendations, now submitted, provide actionable pathways for interdepartmental collaboration. 

One key priority is the ecological restoration of the Pallikaranai Marsh — one of India’s largest remaining urban wetlands and a designated Ramsar site. This marsh plays a vital role in draining floodwaters from the city into the Buckingham Canal and onward to the sea.

The Forest Department has fenced the marsh to prevent encroachments and is undertaking ecological restoration measures such as clearing invasive species like water hyacinth, desilting internal channels and creating a dedicated Wetland Conservation Centre. This centre will serve as a hub for public awareness, education and wetland research. Notably, Tamil Nadu has increased its number of Ramsar sites from just one to 20 in the last four years. This is a testament to the state’s scientific rigour, documentation standards and proactive engagement with the Union Ministry of Environment, Forest and Climate Change.

RK: You spoke about urban flooding in north Chennai. Apart from the restoration of the Pallikaranai Marsh, what steps is Tamil Nadu taking to tackle the issue?

SS: To enhance climate resilience and mitigate flooding, Tamil Nadu has adopted a range of nature-based solutions, particularly in vulnerable zones such as north Chennai. The restoration of the Pallikaranai Marsh is one key example, but equally important are efforts to regenerate coastal ecosystems like mangroves and creeks, which act as natural buffers against climate extremes.

In north Chennai, areas such as Manali and Ennore are both industrially dense and environmentally sensitive. These zones play a critical role in flood dynamics and urban sustainability. Following the oil spill in Ennore two years ago, the Forest Department launched an extensive ecological restoration programme. We not only revived the mangroves damaged by the spill but also expanded the mangrove cover significantly. In Ennore alone, more than 200,000 mangrove saplings have been planted over the last two years.

This is part of a larger state-wide effort. Over the past four years, Tamil Nadu has restored approximately 3,625 hectares of mangrove habitat. These mangroves form the core of what we call a ‘bio-shield’ — a layered defence system using native vegetation to protect coastlines from cyclones, storm surges and erosion. Evidence from the 2004 tsunami and subsequent scientific studies shows that mangrove belts significantly reduce damage to coastal settlements.

The bio-shield approach goes beyond mangroves. In cyclone-prone districts such as Cuddalore, Nagapattinam, Thanjavur, Pudukottai, Tiruvarur and Ramanathapuram, we are creating multi-species protective belts using a combination of casuarina, cashew, palmyra and mangrove plantations, each providing a complementary layer of protection. This work is undertaken in close collaboration with scientific institutions such as the National Centre for Sustainable Coastal Management, National Institute of Ocean Technology, National Centre for Coastal Research and Indian Institute Of Technology Madras.

A key innovation in our mangrove restoration strategy is the adoption of fishbone channel technology, a method used to restore tidal flows in elevated intertidal zones where natural inundation is limited. We have also institutionalised Village Mangrove Councils, community-based bodies involving more than 50 coastal villages. These councils are trained and supported to raise nurseries, maintain plantations, desilt fishbone channels and monitor mangrove health.

Crucially, this initiative directly benefits local livelihoods. Healthy mangrove ecosystems support fish, crab and prawn populations on which many coastal communities depend. Villagers have confirmed that degraded mangroves correlate with reduced catch. The councils also receive seed funding for tools and activities, making this a genuinely community-led climate adaptation model.

RK: Coastal erosion remains a growing concern in Tamil Nadu. What approach is the state taking to address this challenge?

SS: Tamil Nadu is prioritising nature-based solutions as the first line of defence against coastal erosion. With over 1,000 kilometres of coastline, our strategy is to work with nature wherever possible, restoring and reinforcing natural systems that provide long-term protection while supporting biodiversity and local livelihoods.

In erosion-prone stretches, we are promoting mangrove regeneration, coastal bio-shield plantations and dune stabilisation using native vegetation. These living barriers comprising mangroves, casuarina, palmyra, native grasses and indigenous shrubs are carefully selected based on local ecological conditions. 

We are also placing renewed emphasis on protecting and restoring coastal sand dunes, which serve as critical buffers against wave energy and storm surges, especially in southern Tamil Nadu. These dunes are often overlooked, but their conservation is now integral to our coastal resilience strategy.

Where necessary, nature-based measures are complemented by engineered interventions such as groynes or sea walls, but these are implemented only after rigorous scientific assessment and site-specific analysis. We recognise that hard infrastructure can offer localised relief but may lead to unintended consequences downstream if not properly designed. That is why we are working closely with the water resources department, fisheries department and technical agencies to ensure that any structural solution is carefully planned and aligned with the coastal dynamics of adjacent regions.

RK: Climate mitigation and adaptation require significant financial resources. How is Tamil Nadu mobilising climate finance to address this challenge?

SS: Tamil Nadu recognises that climate finance is both a critical enabler and a major hurdle in the journey towards climate resilience. Unlike conventional development projects, climate action demands long-term investment in infrastructure, ecosystems and communities, often without immediate financial returns. This is why we have adopted a systemic and pioneering approach to climate finance and institutional readiness.

We are proud to have established India’s first subnational climate institution, the Tamil Nadu Green Climate Company (TNGCC), a not-for-profit special purpose vehicle created in 2022 under the Government of Tamil Nadu. This dedicated entity anchors the implementation of our four flagship missions: the Green Tamil Nadu Mission, Tamil Nadu Wetlands Mission, Tamil Nadu Climate Change Mission and Tamil Nadu Coastal Restoration Mission.

The TNGCC is governed by a multi-sectoral board chaired by the Additional Chief Secretary, Environment, Climate Change & Forests and includes senior representatives from Finance, Industries, Agriculture, Municipal Administration, Transport, the Pollution Control Board and the Forest Department. This interdepartmental structure ensures integrated planning, cross-sectoral convergence and institutional accountability.

We are actively leveraging multiple streams of climate finance, including World Bank support for the Tamil Nadu Strengthening Coastal Resilience and the Economy (TN SHORE) Project, which anchors the Tamil Nadu Coastal Restoration Mission launched in 2024; National Bank for Agriculture and Rural Development funding for ecosystem-based adaptation; and Japan International Cooperation Agency support for green infrastructure. 

At the same time, we are advocating for greater state budgetary allocations towards climate resilience. We firmly believe that climate action cannot be delayed by waiting for external finance; it must be front-loaded with public investment and supported by strategic co-financing.

RK: The Gulf of Mannar is one of India’s richest marine ecosystems. How is Tamil Nadu working to protect and restore its coral reefs and associated habitats, especially after the global bleaching event in 2024?

SS:  Protecting coral reefs in the Gulf of Mannar is a high priority for Tamil Nadu, not only for their ecological significance but also for their role in coastal resilience and climate adaptation. Our approach is systematic, science-based and community-driven, rather than relying on piecemeal interventions.

We began with detailed mapping of coral reef zones in partnership with institutions such as IIT Madras and the Suganthi Devadason Marine Research Institute. Using this data, we launched phased restoration programmes, starting with degraded reef patches around select islands.

A notable success was the restoration of one island using ferrocement ring structures, which act as artificial substrates for coral polyps to attach and grow. Early monitoring has shown promising signs of coral recovery. Building on this, we have now undertaken restoration of Kariyachalli Island, which, according to scientific projections, could disappear by 2030 if left unrestored. This effort focuses not only on corals but also on seagrass meadows, which are critical feeding grounds for dugongs, an endangered marine mammal found only in a few Indian waters.

In the past four years, we have restored approximately 18 acres of coral reefs and 8 acres of seagrass beds. Our goal is to replicate this across all 21 islands of the Gulf of Mannar in a phased and sustainable manner.

An outstanding feature of this programme is community participation, especially involving local fishers and women’s self-help groups. Traditional fishers, being skilled divers, have become indispensable partners in reef restoration, underwater monitoring and ensuring long-term stewardship. 

We have also introduced an incentive scheme for dugong conservation, under which fishers are rewarded for safely releasing dugongs accidentally caught in fishing nets. In the past four years, eight dugongs, including calves, have been safely released, reinforcing our belief that conservation and livelihoods can go hand in hand.

We are also closely monitoring coral bleaching, which has affected reefs globally, including in Tamil Nadu. The state experienced major bleaching events in 2024, followed by milder bleaching in 2025. However, real-time monitoring systems, developed in collaboration with US agency National Oceanic and Atmospheric Administration and Indian scientific agencies, are showing encouraging signs of recovery this year.

RK: What is Tamil Nadu’s current progress on Coastal Zone Management Plan (CZMP) finalisation and does it include provisions such as long-term housing?

SS: Tamil Nadu’s approach to finalising the CZMP is both comprehensive and consultative. We recognise that this document is not merely a regulatory map. It is a long-term spatial planning tool that must balance ecological sensitivity, community livelihoods and climate resilience.

The plan is currently in an advanced stage of preparation. What sets our effort apart is the extensive stakeholder engagement that underpins it. In all coastal districts, the district collectors have convened structured consultations with fisherfolk, coastal communities, local panchayats and civil society organisations to capture ground realities and incorporate local perspectives into the mapping process.

We are following a rigorous methodology for coastal regulation zone demarcation, using updated high tide line maps, ecologically sensitive area layers and satellite-based land-use data, in line with the 2019 Coastal Regulation Zone (CRZ) Notification.

As for long-term housing, it is certainly being considered as part of the mapping process. However, since this is an evolving and sensitive aspect, particularly in areas prone to erosion, flooding or of high biodiversity value, we are taking a cautious, science-based approach. Until the final maps are vetted and concerns fully addressed, we are not rushing to notify the plan.

Ultimately, our aim is to produce a CZMP that is not only compliant with national regulations but also socially inclusive, climate-informed and implementation-ready — a plan that can genuinely guide sustainable development along Tamil Nadu’s extensive coastline.

RK: Tamil Nadu’s southern coastline was recently impacted by the plastic nurdle spill from the MSC ELSA-III shipwreck off Kerala. How is the state responding to this unprecedented environmental crisis?

SS: The nurdle spill from the MSC ELSA-III cargo vessel, which sank off the Kerala coast on May 24, 2025, has resulted in one of the most significant marine pollution incidents in recent memory. The vessel spilled 640 containers, including plastic nurdles, hazardous chemicals and fuel, leading to widespread contamination along Tamil Nadu’s southern coastline, from Rameswaram to Kanyakumari, affecting more than 40 fishing villages and ecologically sensitive habitats.

Tamil Nadu has mounted a three-pronged response. The first is rapid clean-up and containment. Over 1,270 bags of nurdles, mainly polyethylene, polypropylene, low-density polyethylene and high-density polyethylene, have been collected through joint efforts of district administrations, the Tamil Nadu Pollution Control Board and local communities. Clean-up teams have been mobilised along key beaches, with temporary storage and segregation systems set up.

The second is scientific monitoring and risk assessment. Short-term assessments using drone mapping, water sampling and field surveys are underway. Plans for a long-term impact study, led by key scientific institutions, will assess ecosystem risks to coral reefs, seagrass beds, aquaculture zones and food chains. Nurdles are known to carry and release toxic chemicals, degrade into microplastics and threaten marine biodiversity and fisheries.

The third is policy and legal preparedness. We are initiating a dedicated standard operating procedure for plastic pellet spills, drawing lessons from this event. Compensation efforts will be evidence-based, in line with Central Pollution Control Board guidelines. Tamil Nadu is coordinating with central agencies and scientific bodies to strengthen marine plastic disaster protocols at the national level.

RK: Beyond climate and pollution concerns, how is Tamil Nadu tackling biodiversity protection?

SS: Tamil Nadu has emerged as a national frontrunner in biodiversity conservation, with a focus on expanding protected areas, restoring critical habitats and mainstreaming community and youth participation in conservation.

Over the past four years, we have notified India’s first Dugong Conservation Reserve in the Gulf of Mannar, the country’s first Slender Loris Sanctuary across Karur and Dindigul and, most recently, the Agasthyamalai Elephant Reserve, the first elephant reserve to be declared in India in over two decades. Together, these new designations add nearly 300,000 hectares to our network of legally protected areas.

We are also reviving flagship species such as the Nilgiri tahr, an endemic and endangered mountain ungulate of the Western Ghats. Through scientific surveys, radio-collaring and habitat assessments, we are now preparing to reintroduce the species into historically documented ranges.

Tamil Nadu’s conservation strategy is not confined to protected zones. We are investing in species-specific and habitat-focused conservation centres for migratory birds, dugongs and seagrass, slender loris, turtles and the Nilgiri tahr. These hubs integrate research, education and community stewardship, linking biodiversity protection directly with climate resilience.

To cultivate future leaders in conservation, we have launched the Green Fellowship Programme, under which 40 young professionals are placed in districts to support mission-driven implementation, ecological monitoring and grassroots engagement. They receive monthly stipends and hands-on training, ensuring that Tamil Nadu’s environmental future is shaped by both expertise and commitment.

RK: Looking ahead, what is Tamil Nadu’s broader vision for environmental sustainability and how does it aim to balance development with conservation?

SS: Tamil Nadu’s environmental vision is rooted in the belief that climate resilience, ecological integrity and inclusive development must go hand in hand. We are not merely reacting to environmental challenges, we are designing systems that anticipate and adapt to them.

At the heart of this vision is a mission-driven, institutionalised approach. Our four flagship initiatives (the Green Tamil Nadu Mission, Tamil Nadu Wetlands Mission, Tamil Nadu Climate Change Mission and TN SHORE) work in synergy to address the state’s most pressing ecological and climate challenges. Each mission is supported by dedicated governance structures, scientific advisory inputs, financial frameworks and community partnerships.

What sets Tamil Nadu apart is the integration of environmental thinking across sectors, urban planning, agriculture, industry, education and health. Whether it is greening industrial campuses, solarising schools, restoring mangroves, conserving marine species or tackling air pollution in cities, we are embedding sustainability into everyday governance.

We also recognise the power of people’s participation. Environmental stewardship lies at the core of Tamil Nadu’s development model. We are working to ensure that our ecosystems are not just protected, but revived and future-proofed. The path we are charting today is not only for the present generation, it is a conscious legacy we are building for generations to come.