Important Wetlands and Ramsar Sites in India

Wetlands are ecosystems where water covers the soil or is present near the surface for varying periods during the year. They act as natural sponges, filtering water, controlling floods, recharging groundwater, and serving as critical habitats for biodiversity. In India, wetlands span vast inland freshwater lakes, riverine floodplains, coastal estuaries, brackish lagoons, and high-altitude lakes. To conserve these vital ecosystems, international and national frameworks regulate their protection, most prominent among which is the Ramsar Convention on Wetlands.

The Ramsar Convention and Legal Framework in India

The Ramsar Convention is an intergovernmental treaty adopted on February 2, 1971, in the Iranian city of Ramsar. It entered into force in 1975. India officially became a contracting party to the convention on February 1, 1982.

Definition of Wetlands

Under Article 1.1 of the Ramsar Convention, wetlands are 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.

National Regulatory Architecture

In India, domestic wetland protection operates under the Wetlands (Conservation and Management) Rules, 2017, notified under the Environment (Protection) Act, 1986. These rules decentralized wetland administration by establishing State Wetland Authorities in every state and Union Territory. The regulations explicitly prohibit activities such as industrial establishment, solid waste dumping, discharge of untreated effluents, and construction of permanent structures on designated wetland areas.

Ramsar Selection Criteria and the Montreux Record

A wetland qualifies as a Ramsar site if it satisfies at least one of nine specific criteria established by the convention. These criteria fall into two broad categories: Group A (sites containing representative, rare, or unique wetland types) and Group B (sites of international importance for conserving biological diversity based on species, ecological communities, waterbirds, or fish).

The Montreux Record

The Montreux Record is a register of wetland sites on the List of Ramsar Wetlands of International Importance 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. It is maintained as part of the Ramsar List.

• Keoladeo National Park (Rajasthan): Placed on the Montreux Record in 1990 due to water shortage and dominant growth of the invasive weed Paspalum distichum.
• Loktak Lake (Manipur): Placed on the Montreux Record in 1993 due to ecological problems resulting from deforestation in the catchment area, siltation, and the construction of the Ithai Barrage.
• Chilika Lake (Odisha): Added to the Montreux Record in 1993 due to siltation and choking of the lake mouth. It was successfully removed from the record in 2002 after the Odisha government opened a new sea mouth, restoring the estuarine ecosystem. This earned the Chilika Development Authority the Ramsar Wetland Conservation Award.

Geographic Distribution and Major Wetland Systems

India hosts a diverse array of wetland ecosystems distributed across its varied geographical zones. Tamil Nadu holds the highest number of designated Ramsar sites among all Indian states, followed by Uttar Pradesh.

Inland Freshwater Wetlands

• Wular Lake (Jammu & Kashmir): One of the largest freshwater lakes in Asia, formed by tectonic activity and fed by the Jhelum River.
• Loktak Lake (Manipur): The largest freshwater lake in northeastern India, famous for phumdis (floating heterogeneous masses of vegetation, soil, and organic matter) and hosting the endangered Sangai deer in Keibul Lamjao National Park.
• Kanwar Taal / Kabar Taal (Bihar): A oxbow lake formed by the meandering of the Burhi Gandak River, acting as a vital stopover on the Central Asian Flyway.
• Bhoj Wetland (Madhya Pradesh): Consists of two man-made reservoirs, the Upper Lake (Bada Talaab) and Lower Lake (Chhota Talaab), created in the 11th century.

Coastal and Brackish Lagoons

• Sundarban Wetland (West Bengal): The largest contiguous mangrove forest system in the world and the largest Ramsar site in India, located at the delta formed by the Super Confluence of the Ganges, Brahmaputra, and Meghna rivers.
• Chilika Lake (Odisha): Asia’s largest brackish water lagoon, famous for wintering migratory birds and a resident population of Irrawaddy dolphins.
• Vembanad-Kol Wetland (Kerala): The longest lake in India and the largest wetland complex in Kerala, lying below sea level and fed by ten rivers.

High-Altitude and Desert Wetlands

• Tsomoriri and Tso Kar (Ladakh): High-altitude saline and brackish lakes located in the Changthang region, serving as breeding grounds for the endangered Black-necked Crane.
• Chandra Taal (Himachal Pradesh): A high-altitude lake near the Samudra Tapu plateau in the Spiti valley.
• Sambhar Lake (Rajasthan): India’s largest inland saline lake, receiving water from five rivers including the Luni and Mendha.

Comparative Matrix of Prominent Indian Ramsar Sites

Threats and Ecological Challenges

Indian wetlands face severe pressures despite statutory protection mechanisms.

• Siltation and Encroachment: Deforestation in catchment areas increases soil erosion, leading to rapid siltation that reduces water storage capacity. Urban expansion leads to drainage and reclamation of wetland beds for real estate.
• Invasive Species: Fast-spreading alien species such as Water Hyacinth (Eichhornia crassipes) and Prosopis juliflora disrupt native biodiversity, clog waterways, and diminish dissolved oxygen levels.
• Agricultural Run-off: Excessive chemical fertilizers and pesticides entering wetland waters trigger eutrophication, causing massive algal blooms and severe hypoxic conditions.
• Hydrological Disruption: Dams, barrages, and water diversions upstream alter natural flow regimes, preventing seasonal flushing and increasing salinity imbalances in estuarine systems.

Key Facts

• February 2 is celebrated globally as World Wetlands Day to mark the adoption of the Ramsar Convention in 1971.
• Chilika Lake (Odisha) and Keoladeo National Park (Rajasthan) were the first two sites in India designated under the Ramsar Convention on October 1, 1981.
• Sundarban Wetland in West Bengal is the largest Ramsar site in India, covering over 4,200 square kilometers.
• Renuka Lake in Himachal Pradesh and Vembannur Wetland Complex in Tamil Nadu are among the smallest Ramsar sites in India by area.
• Tamil Nadu has the highest number of Ramsar sites in India with 20 designated wetlands.
• Keoladeo National Park and Loktak Lake are the two Indian sites currently listed on the Montreux Record.
• Chilika Lake is the only Indian site to date that was added to the Montreux Record and subsequently removed after successful ecological restoration.
• Lonar Lake in Maharashtra is a unique Ramsar site created by a meteor impact in Deccan basalt.
• Keibul Lamjao National Park on Loktak Lake is the world’s only floating national park.
• Central Asian Flyway (CAF) covers a vast area of Eurasia between the Arctic and Indian Oceans, with Indian wetlands serving as critical wintering stops for migratory waterbirds.