Wetlands are ecotones or transitional zones between terrestrial and aquatic ecosystems where the water table is usually at or near the surface, or the land is covered by shallow water. Under the Ramsar Convention, wetlands are broadly defined as areas of marsh, fen, peatland, or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish, or salt, including areas of marine water the depth of which at low tide does not exceed six meters.
Statistical Overview and Spatial Distribution
According to the National Wetland Decadal Change Atlas compiled by the Space Applications Centre (SAC-ISRO), wetlands cover approximately 15.26 million hectares, representing roughly 4.63% of India’s total geographical area.
Inland vs. Coastal Structural Division
- Inland Natural Wetlands: Account for approximately 43.4% of the total wetland area, dominated by waterlogged areas, seasonal oxbow lakes, and high-altitude alpine lakes.
- Inland Man-made Wetlands: Represent about 25.8% of the total wetland area, consisting primarily of irrigation tanks, farm ponds, and major river valley reservoirs.
- Coastal Natural Wetlands: Comprise roughly 24.3% of the total area, including mangroves, coral reefs, intertidal mudflats, sea-grass beds, and estuaries.
- Coastal Man-made Wetlands: Account for nearly 6.5% of the total wetland extent, primarily used for aquaculture ponds and salt pans.
State-wise Concentration Metrics
- Gujarat: Possesses the highest total wetland area in India, covering over 3.47 million hectares, which accounts for more than 22% of the national wetland footprint. This is driven by its extensive salt pans, intertidal mudflats, and coastal lagoons.
- Other Leading States: Andhra Pradesh, Uttar Pradesh, West Bengal, and Maharashtra follow Gujarat in terms of total wetland area, each characterized by expansive deltaic networks or inland riverine basins.
The Ramsar Convention and India’s Strategic Footprint
India became a contracting party to the Ramsar Convention on February 1, 1982. The country hosts over 80 designated Wetlands of International Importance (Ramsar Sites), covering an aggregate surface area of more than 1.3 million hectares.
The Montreux Record and India’s Vulnerable Sites
The Montreux Record is a principal register under the Ramsar Convention listing sites where changes in ecological character have occurred, are occurring, or are likely to occur as a result of technological developments, pollution, or other human interference. Currently, two Indian wetlands remain on the Montreux Record:
- Loktak Lake (Manipur): Placed on the record in 1993 due to ecological degradation, deforestation in the catchment area, and the impacts of the Ithai Hydropower Barrage, which disrupted the natural seasonal water level fluctuations and threatened the floating phumdis.
- Keoladeo National Park (Rajasthan): Listed in 1990 due to chronic water scarcity caused by the diversion of water from the Ajan Dam, leading to the proliferation of invasive weeds like Prosopis juliflora and a drop in migratory avifauna nesting sites.
The Chilika Lake Rehabilitation Model
Chilika Lake (Odisha) was added to the Montreux Record in 1993 because a choking of its tidal inlet mouth led to a drop in salinity levels, a proliferation of invasive weeds, and a collapse of local fisheries. In 2000, the Chilika Development Authority (CDA) opened a new artificial mouth directly into the Bay of Bengal, restoring the salinity gradient. This intervention successfully revived the ecosystem, leading to Chilika becoming the first Asian wetland to be removed from the Montreux Record in 2002.
Comprehensive Compendium of Key Indian Ramsar Sites
| Wetland Name | Location (State/UT) | Ecosystem Category | Hydro-Geomorphic and Ecological Highlights |
| Sundarbans | West Bengal | Coastal Mangrove | The largest Ramsar site in India; forms part of the world’s largest deltaic mangrove forest; exclusive habitat for the Royal Bengal Tiger (Panthera tigris). |
| Vembanad-Kol | Kerala | Brackish Backwater / Estuary | The longest wetland system in India; features the Thanneermukkom Saltwater Barrier; includes low-altitude below-sea-level farming zones in Kuttanad. |
| Chilika Lake | Odisha | Brackish Coastal Lagoon | India’s first designated Ramsar Site; major wintering destination along the Central Asian Flyway; supports the vulnerable Irrawaddy Dolphin (Orcaella brevirostris). |
| Loktak Lake | Manipur | Inland Freshwater | Characterized by floating heterogeneous masses of soil and vegetation called phumdis; hosts the Keibul Lamjao National Park (the world’s only floating national park). |
| Sambhar Lake | Rajasthan | Inland Saline Depression | India’s largest inland salt lake; endorheic structural basin fed by four seasonal streams; designated a key site for migratory flamingos. |
| Kabartal / Kanwar Lake | Bihar | Fluvial Freshwater Oxbow | Asia’s largest freshwater oxbow lake, formed by the meandering of the Gandak River; critical refuge for the critically endangered Oriental White-backed Vulture. |
| Asan Barrage | Uttarakhand | Man-made Riverine | Uttarakhand’s first Ramsar site, situated at the confluence of the Asan River and the Yamuna Canal; critical staging site for trans-Himalayan migratory ducks. |
| Tso Kar Complex | Ladakh | Trans-Himalayan Hyper-saline | Includes the hyper-saline Startsapuk Tso and the fresh Tso Kar lake; primary breeding ground for the vulnerable Black-necked Crane (Grus nigricollis). |
| Harike Lake | Punjab | Man-made Confluence | An artificial reservoir formed by a barrage at the confluence of the Beas and Satluj rivers; the source of the Indira Gandhi Canal. |
| Bhoj Wetland | Madhya Pradesh | Man-made Urban | Comprises the Upper Lake (Bhojtal) and Lower Lake; created in the 11th century by Raja Bhoj across the Kolans River. |
| Deepor Beel | Assam | Fluvial Freshwater | A permanent freshwater lake located in a former channel of the Brahmaputra River; the only Ramsar site in Assam; threatened by urban encroachment. |
| Point Calimere | Tamil Nadu | Coastal Marine / Marsh | Consists of shallow waters, salt swamps, and sand dunes; includes the Great Vedaranyam Swamp; critical feeding ground for lesser and greater flamingos. |
| Pala Wetland | Mizoram | Inland Freshwater | The largest natural wetland in Mizoram, surrounded by lush tropical rainforests; holds cultural significance for the local Mara tribe. |
| Thol Lake | Gujarat | Man-made Reservoir | A shallow freshwater reservoir surrounded by agricultural fields, supporting high concentrations of waterbirds along the Central Asian Flyway. |
Special Ecological and Morphological Phenomena
The Morphological Dynamics of Phumdis
The phumdis of Loktak Lake are floating mats of organic debris, soil, and vegetation at varying stages of decomposition. They maintain a seasonal cycle: during the monsoon, when water levels rise, the phumdis float freely. In the dry summer months, water levels drop, causing the heavy roots of the phumdis to touch the lake bed, where they absorb essential sub-surface soil nutrients. This nutrient absorption sustains the vegetation, which supports the endangered Sangai or brow-antlered deer (Rucervus eldii eldii).
The Hydro-Engineering Divide of Kuttanad
The Vembanad-Kol wetland system is split into two hydrographic zones by the Thanneermukkom Bund. This barrier prevents tidal seawater ingress into the low-lying Kuttanad valley, where agriculture is practiced nearly two meters below sea level. The barrier ensures the southern sector remains a freshwater basin fed by the Pamba and Achankovil rivers, while the northern sector remains brackish and connected to the Arabian Sea at the Kochi port inlet.
Oxbow Lake Evolution in the Gangetic Floodplains
The Indo-Gangetic plains feature numerous oxbow lakes, locally termed chaur or beel. These lakes form when highly mature, meandering rivers cut off a pronounced loop during monsoonal floods to find a shorter path. Kanwar Lake (Kabartal) in Bihar is an example of this geomorphic process, formed by historical changes in the course of the Gandak River.
Regulatory Frameworks and National Conservation Programs
Wetlands (Conservation and Management) Rules, 2017
Promulgated under the Environment (Protection) Act, 1986, these statutory rules establish the regulatory framework for protecting non-Ramsar wetlands in India.
- State Wetland Authorities (SWAs): The rules decentralized water governance by mandating that each state setup an SWA to handle boundary mapping, ecological auditing, and notification of local wetlands.
- Prohibited Activities: The rules impose a strict nationwide ban on reclaiming wetlands, setting up new industries within notified zones, dumping solid waste, or discharging untreated domestic and industrial effluents into wetland catchments.
National Plan for Conservation of Aquatic Eco-systems (NPCA)
The Ministry of Environment, Forest and Climate Change administers the NPCA, which was formed by merging the National Lake Conservation Plan with the National Wetlands Conservation Programme. Operating under a cost-sharing mechanism between central and state governments, it funds core interventions including shoreline bio-fencing, mechanical de-siltation of tidal inlets, weed control, and community-led eco-tourism programs.
The Amrit Dharohar Capacity Building Scheme
Launched to promote the conservation values of Ramsar sites, this national program focuses on generating alternative livelihoods for local communities through sustainable eco-tourism, nature guiding, and organic wetland agriculture. It aims to transform communities into local guardians of these fragile aquatic ecosystems.
Primary Ecological Threats to Indian Wetlands
- Anthropogenic Eutrophication: Runoff containing chemical fertilizers from adjacent agricultural zones and untreated domestic sewage dump large volumes of nitrogen and phosphorus into wetlands. This nutrient enrichment triggers rapid algal blooms that deplete dissolved oxygen, leading to the collapse of benthic fauna and local fish populations.
- Invasive Species Encroachment: The uncontrolled proliferation of invasive alien weeds, such as the Water Hyacinth (Eichhornia crassipes) and water fern (Salvinia molesta), creates thick surface mats that block sunlight penetration, disrupting the aquatic food web and choking local navigation channels.
- Siltation and Shoaling: Deforestation, unscientific road cutting, and livestock overgrazing in upper catchments increase soil erosion. feader streams carry this heavy sediment load downstream, where it deposits on wetland beds, systematically reducing their water-holding capacity.
- Agricultural Reclamation and Urban Sprawl: Growing population pressure leads to the conversion of wetland margins into commercial aquaculture ponds (gheries) or urban housing tracts, disrupting natural drainage networks and increasing the risk of urban flash floods.
Civil Services Fact-File and Exam Trivia
The Artificial Island of Zaina Lank
Sultan Zain-ul-Abidin of Kashmir constructed an artificial island named Zaina Lank in the middle of Wular Lake during the 15th century. It was engineered using stone masonry to provide a safe anchorage site for boats during sudden monsoonal storms on the open lake.
The Indus Waters Treaty Boundary
Harike Wetland in Punjab sits at a critical hydro-geographic node. The water diverted from its barrage via the Indira Gandhi Canal runs through the Thar Desert to Jaisalmer, providing irrigation to western Rajasthan while acting as a strategic geographic buffer zone along the international border with Pakistan.
The Space Shield of Pulicat Lake
The barrier island of Sriharikota, which structurally isolates Pulicat Lake from the open sea, forms the natural geographic location for the Satish Dhawan Space Centre. The extensive, uninhabited water sheet of the surrounding lagoon provides an important acoustic cushion and safety buffer zone for polar and geosynchronous rocket launch paths.
The Changthang Salt Trading Legacy
The hyper-saline nature of the Tso Kar complex in Ladakh causes a thick white crust of sodium sulfate to deposit along its banks. Historically, this salt was harvested by the local nomadic Changpa tribes for trade across the Tibetan plateau long before the site was designated as a Ramsar wetland.
Last Modified: June 6, 2026