CHENNAI: The southern bench of the National Green Tribunal (NGT) has directed that no planning permission or construction approval be granted in or around the Pallikaranai Marshland until an Integrated Management Plan (IMP) is finalised and the Tamil Nadu State Wetland Authority (TNSWA) determines the zone of influence of Chennai’s last surviving wetland.
Delivering a landmark order in a suo motu case on Wednesday, judicial member Justice Pushpa Sathyanarayana and expert member Prashant Gargava made it clear that the Chennai Metropolitan Development Authority (CMDA), TNSWA and water resources department (WRD) must coordinate to complete the IMP and scientifically delineate the “zone of influence” of the Ramsar site before allowing any development.
The case was registered based on a TNIE article published in June 2023, highlighting a road being laid across the Perumbakkam marshland using construction debris. The tribunal took cognisance and issued notices to state agencies and private developers, including Casagrand Builders and Grande City Development Company LLP.
Chengalpattu collector’s first inspection in August 2023 found that the road and buildings were coming up on marshland, including areas owned by the forest department. However, while survey number 534/4 was classified as marshland, the disputed survey numbers 286 and 285 were recorded as patta ‘ryotwari wetlands’, raising questions over ownership and land use.
The CMDA, in multiple reports through 2024 and 2025, maintained that permissions were issued only based on official revenue records that listed the land as private patta within a “primary residential use zone”. It argued it had not approved projects on lands earmarked as marsh in the second master plan, but admitted it was still awaiting precise survey data from the TNSWA to incorporate Ramsar site boundaries into the upcoming third master plan.
The TNSWA, in its inspections in July 2023 found that debris was being dumped within 150m of the Ramsar site boundary. It cited the IMP prepared by Care Earth Trust, which recommended a 1-km buffer around the marsh, noting that feeder canals from Perumbakkam lake passed through survey number 286 and were vital to the marsh’s hydrology. In July 2025, the TNSWA further warned that altering stormwater inlets and drainage channels could disrupt flood flows, exposing local communities to inundation.
The WRD also raised flood concerns and recommended raising field levels and incorporating flood-mitigation structures before any construction.
The builders, however, denied constructing a road, claiming they only levelled patta land with scrap materials for survey purposes. They insisted that survey number 286 had not been formally notified as wetland under the Wetlands Rules, 2017, and was zoned residential.
The NGT stressed that precautionary principles must prevail. “Even assuming the site is patta land, it lies less than 150m from the Ramsar boundary and falls within the zone of influence of the marsh,” the order stated. The tribunal observed that while permissions had been granted earlier for projects in nearby survey numbers 470 and 471, such precedents cannot justify new clearances in ecologically-sensitive zones, especially when the IMP revision is underway.
Timeline of the Perumbakkam marsh case
June 30, 2023 TNIE reports road construction across Perumbakkam marshland; NGT takes suo motu cognisance
Aug 7, 2023 Chengalpattu collector’s inspection finds building activity inside marshland, classifies parts as forest department land
Aug 23, 2023 TNSWA reports dumping of debris within 150m of Ramsar site, warns of adverse ecological impact
January-August 2024 CMDA says lands are patta, zoned residential. Claims no approvals given in marsh areas earmarked under second master plan. Admits awaiting precise survey data from TNSWA
Sept-Oct 2024 Collector’s subsequent reports confirm survey numbers 285 and 286 are patta ‘ryotwari wetlands’, not government poramboke; notes historical classification as private patta since 1911
July 2025 TNSWA submits detailed report. Identifies 304 survey numbers across seven villages falling within Pallikaranai Ramsar site. Warns that construction in survey number 286 could block feeder canals and stormwater inlets
July-August 2025 WRD recalls 2015 and 2023 floods, recommends raising site levels, flood mitigation structures. Builders argue they only levelled patta land for survey
Sept 24, 2025 NGT orders no approvals until Integrated Management Plan (IMP) is finalised