Interim zone of influence around Pallikaranai marshland can be restricted to 36 survey numbers, State Wetlands Authority tells Madras High Court

Environment and Ecology · 13 October 2026 · Based on The Hindu (original report)

Must read — 2 past UPSC questions on this theme (Prelims GS-1 2019, Prelims GS-1 2022); also both a Prelims fact and a Mains debate.

2-minute summary

In a major relief to property owners facing a construction ban near the Pallikaranai marshland in Chennai, the Tamil Nadu State Wetlands Authority (TNSWA) informed the Madras High Court that the interim zone of influence (ZoI) can be restricted to 36 survey numbers covering approximately 128.19 hectares. The interim ZoI was proposed following a challenge by the Confederation of Real Estate Developers Association of India (CREDAI) against an earlier National Green Tribunal (NGT) blanket one-kilometre radius ban. The TNSWA clarified that construction within the interim ZoI will not be completely banned but will be strictly regulated based on site-specific scientific and hydrological characteristics. Prohibitions include blocking natural drainage pathways, dumping solid or construction waste, discharging untreated sewage, and operating red category industries. Furthermore, developers must obtain a No Objection Certificate (NOC) from the district-level wetlands management committee. The final ZoI will be determined following comprehensive scientific and cadastral ground truthing in accordance with the Wetlands (Conservation and Management) Rules, 2017.

Why it's in the news

The Tamil Nadu State Wetlands Authority informed the Madras High Court that the interim zone of influence around the Pallikaranai marshland can be restricted to 36 survey numbers (128.19 hectares), offering a balanced approach between urban development and ecological conservation.

Facts to remember

Pallikaranai marshland is a designated Ramsar site located in Chennai, Tamil Nadu.
The Tamil Nadu State Wetlands Authority proposed restricting the interim zone of influence to 36 survey numbers covering 128.19 hectares.
The Wetlands (Conservation and Management) Rules were framed under the Environment (Protection) Act, 1986.
Red category industries with high pollution potential are strictly prohibited within the interim zone of influence around the wetland.
Construction activities within the interim ZoI require a No Objection Certificate from the district level wetlands management committee.

Background and context

The Pallikaranai marsh is a freshwater marshland and one of the last surviving natural ecosystems of Chennai. It acts as a vital natural sponge, absorbing excess rainwater and mitigating floods in the southern suburbs of the city. Over decades, rapid urbanization, real estate encroachment, and dumping of municipal solid waste have severely degraded its ecological integrity. Legal battles involving bodies like the National Green Tribunal (NGT) and the Madras High Court have sought to protect its boundaries by demarcating a 'Zone of Influence' (ZoI) or buffer zone. However, blanket bans on construction across wide radii often trigger friction between urban development needs and environmental jurisprudence, leading to nuanced regulatory frameworks like the current interim identification of specific survey numbers by the State Wetlands Authority.

Constitutional provisions

Article 48A — Directs the State to endeavor to protect and improve the environment and to safeguard the forests and wildlife of the country.
Article 51A(g) — Imposes a fundamental duty on every citizen of India to protect and improve the natural environment including forests, lakes, rivers, and wildlife.

Government schemes

National Plan for Conservation of Aquatic Ecosystems (NPCA) — Central sector scheme aimed at conservation and management of wetlands and lakes in the country on a cost-sharing basis between Central and State Governments.

International organisations

Ramsar Convention on Wetlands — An intergovernmental treaty providing the framework for national action and international cooperation for the conservation and wise use of wetlands and their resources.

Previous UPSC questions on this theme

Prelims GS-1 2019 — Consider the following statements : 1. Under Ramsar Convention, it is mandatory on the part of the Government of India to protect and conserve all the wetlands in the territory of India. 2. The Wetlands (Conservation and Management) Rules, 2010 were framed by the Government of India based on the recommendations of Ramsar Convention. 3. The Wetlands (Conservation and Management) Rules, 2010 also encompass the drainage area or catchment regions of the wetlands as determined by the authority. Which of the statements given above is/are correct? (a) 1 and 2 only (b) 2 and 3 only (c) 3 only (d) 1, 2 and 3
Prelims GS-1 2022 — "If rainforests and tropical forests are the lungs of the Earth, then surely wetlands function as its kidneys." Which one of the following functions of wetlands best reflects the above statement ? (a) The water cycle in wetlands involves surface runoff, subsoil percolation and evaporation. (b) Algae form the nutrient base upon which fish, crustaceans, molluscs, birds, reptiles and mammals thrive. (c) Wetlands play a vital role in maintaining sedimentation balance and soil stabilization. (d) Aquatic plants absorb heavy metals and excess nutrients.

Mains practice: Examine the ecological significance of urban wetlands and discuss the regulatory mechanisms required to balance urban growth with wetland preservation.

Urban wetlands function as the 'kidneys' of the earth, performing crucial hydrological, ecological, and micro-climatic roles such as flood mitigation, groundwater recharge, and pollutant filtration. The Pallikaranai marshland in Chennai, a designated Ramsar site, exemplifies both the ecological vulnerability of urban water bodies and the severe pressures of real estate encroachment.

• Ecological and Hydrological Role: Wetlands act as natural sponges that absorb heavy monsoon runoff, preventing urban inundation. They trap sediments, absorb heavy metals, and support rich biodiversity, aligning with Article 48A of the Constitution which directs the State to protect the environment.

• Regulatory and Legal Framework: The Wetlands (Conservation and Management) Rules, 2017, framed under the Environment (Protection) Act, 1986, mandate state-level authorities to notify wetlands and regulate activities within their zones of influence (ZoI). Judicial interventions by bodies like the National Green Tribunal (NGT) and High Courts often establish protective buffers to halt unregulated construction.

• Development vs. Conservation Trade-off: Blanket bans across arbitrary radii (such as a 1 km radius) create severe socio-economic friction with private landholders and developers. A science-based, cadastral approach—such as restricting the interim ZoI to specific survey numbers based on hydrological pathways—reconciles ecological preservation with orderly urban growth.

• Institutional Accountability: Effective governance requires strict prohibition of red-category industries, solid waste dumping, and sewage discharge into wetland channels, backed by statutory clearances from district-level wetland management committees.

Way Forward:

1. State Wetlands Authorities must expedite scientific ground-truthing and final notification of wetland boundaries and their zones of influence.

2. Implement rigorous GIS-based monitoring to prevent illegal encroachments and blocking of natural drainage channels.

3. Integrate wetland conservation plans into urban master plans to ensure sustainable municipal growth.

Conclusion:

Balancing urban expansion with wetland conservation is critical for climate resilience. Upholding environmental rule of law while adopting pragmatic, science-based regulatory frameworks fulfills India's commitments under international conventions like Ramsar and advances the Sustainable Development Goals (SDG 11 and 15).

Prelims practice questions

Q1. Consider the following statements regarding the Wetlands (Conservation and Management) Rules, 2017: 1. The rules prohibit activities such as permanent conversion of wetlands for non-wetland uses and solid waste dumping within notified wetlands. 2. The management of wetlands under these rules is centrally coordinated exclusively by the National Wetland Authority without state-level bodies. 3. The rules apply uniformly to all water bodies, ponds, and rivers irrespective of their size and ecological significance. How many of the above statements are correct?

Only one
Only two
All three
None

Answer: A. Statement 1 is correct because the Wetlands Rules, 2017 explicitly prohibit prohibited activities like conversion for non-wetland uses and solid waste dumping within wetlands. Statement 2 is incorrect because the rules establish State Wetlands Authorities for decentralized management and identification of wetlands. Statement 3 is incorrect because the rules exclude river channels, paddy fields, and certain human-made water bodies from their purview, focusing primarily on ecologically significant wetlands.

Q2. Consider the following statements: Statement-I: Pallikaranai marshland, located in Chennai, is a designated Ramsar site renowned for its ecological role in flood mitigation and groundwater recharge. Statement-II: The Ramsar Convention mandates contracting parties to formulate and implement planning to promote the conservation of wetlands and their wise use. Which one of the following is correct in respect of the above statements?

Both Statement-I and Statement-II are correct and Statement-II explains Statement-I
Both Statement-I and Statement-II are correct but Statement-II does not explain Statement-I
Statement-I is correct but Statement-II is incorrect
Statement-I is incorrect but Statement-II is correct

Answer: B. Statement-I is factually correct as Pallikaranai marsh is a Ramsar site in Chennai serving crucial hydrological functions. Statement-II is also correct as it states the core mandate of the Ramsar Convention. However, Statement-II is an international treaty obligation and does not directly explain the specific local ecological characteristics of the Pallikaranai marsh mentioned in Statement-I.

Q3. Which one of the following authorities is primarily responsible for identifying and notifying wetlands and recommending regulatory measures for their conservation at the state level in India?

State Disaster Management Authority
Central Pollution Control Board
National Biodiversity Authority
State Wetlands Authority

Answer: D. Under the Wetlands (Conservation and Management) Rules, 2017, each State and Union Territory must establish a State Wetlands Authority to prepare a brief document on wetlands, define their zones of influence, and regulate activities within them.

Revision flashcards

Under which statutory framework are the Wetlands (Conservation and Management) Rules framed in India? The Environment (Protection) Act, 1986.
What is the primary international treaty dedicated to the conservation and wise use of wetlands? The Ramsar Convention on Wetlands (signed in 1971).
In October 2026, the Tamil Nadu State Wetlands Authority informed the Madras High Court that the interim zone of influence around Pallikaranai marshland can be restricted to how many survey numbers? 36 survey numbers covering approximately 128.19 hectares.
What city hosts the Pallikaranai marshland, a prominent urban Ramsar site in India? Chennai, Tamil Nadu.
Why is the demarcation of a 'Zone of Influence' around wetlands legally significant? It regulates developmental activities, prevents blocking of natural drainage pathways, and balances urban expansion with ecological preservation.