The East Calcutta Wetlands, also known as the East Kolkata Wetlands, are a complex of natural and human-made wetlands lying east of the city of Calcutta (Kolkata), West Bengal in India. The wetlands cover 125 square kilometres, and include salt marshes and salt meadows, as well as sewage farms and settling ponds. The wetlands are used to treat Kolkata's sewage, and the nutrients contained in the wastewater sustain fish farms and agriculture.
The East Calcutta Wetlands were designated a "wetland of international importance" under the Ramsar Convention on August 19, 2002.
Recently illegal landfills are on the rise and the wetlands are being slowly assimilated in the mainstream city. This unprecedented land development and urbanization are creating concerns about the impact on the environment. This is because the wetlands serve as a natural sponge absorbing excess rainfall and doing its bit to reduce pollution. In fact its greatest gift to Kolkata is its use as a natural bio-waste disposal cum treatment facility.