1865: Acquisition of a 1-square mile area by the municipal authorities for dumping the city's garbage.

1868-1872: Construction of a railway line and a canal were constructed across the square mile area.

1884: Completion of the drainage scheme with canals and sluices across the wetlands for the disposal of sewage and storm water to the Bidyadhari and Malta rivers.

1940: The sewage outfall of Calcutta was changed from southeast to east to the Kutli Gong when the Bidyadhari dried up.

1962-1967: Large-scale reclamation for extension of the city of Calcutta.

1980: Beginning of environmental concern for traditional reuse practices in the Calcutta wetlands and the first conscious efforts to conserve the wetlands. The first report on the environment of the area came out in 1983.

1985: Mapping of the waste recycling region and wetland use. Promotion of the wetland pond system by a number of municipalities to replace conventional sewage treatment plants for municipal sanitation and resource recovery under the Ganga Action Plan.

1986: Beginning of the Mudially Fishermen's Cooperative Society on 80 ha of wetlands belonging to the Calcutta Port Trust. The society treats 25 million litres of city sewage daily to produce 280 tonnes of fish every year.

1991: Public interest litigation filed by Calcutta-based NGO, PUBLIC, against the state government and builders working on reclaiming wetlands for real estate development.

1992: Calcutta High Court ruling against reclamation of wetlands.

1993: Proposal to include Calcutta wetlands in the list of wetlands of national importance.