As one of the cities to be worst affected by a changing climate and at an increased risk of flooding, Kolkata needs to preserve its wetlands much more urgently than other cities!

According to the World Bank, a rise of even 20 cm in sea levels can make Kolkata one of the three most flood prone cities in the world!

Kolkata’s temperature is predicted to rise by 1.2 ºC to 1.8 ºC by 2050 with a corresponding rise of 27 cm in its sea level within the next four decades.

The story of Kolkata reveals a tragic irony. One of the most water-rich cities in the country – with the Ganga flowing on its western end, a number of wetlands on the eastern fringe and traditionally abundant reserves of groundwater – Kolkata, today, is majorly water stressed.

In 2005-06, the water demand of the city was 925 MLD. However, its supply ran short by a full 135 MLD, creating a crisis situation for many residents.


  • Unchecked construction projects

  • pollution

  • falling groundwater levels

  • rising population

Falling groundwater levels, unchecked consumption, independent extraction of groundwater and pollution are reasons the city is running dry! From 1996 to 2006, there has been a considerable and consistent drop in Kolkata’s groundwater levels. Up to 25% to 30% of the water being used in households is ground water.

Despite having water connections, families living in newly constructed multi-story apartment complexes pump their own water as they do not have much faith in the quality of water supplied by civic bodies. As a result, groundwater levels have plummeted in various parts of Kolkata.

More than 315 million gallons of drinking water is withdrawn daily from the KMC area, with a per capita consumption of nearly 200 litres per day.

Since the city dwellers draw out their own water, they are not liable to pay any water tax as per a declared mandate of the government. This has been leading to a great amount of wastage and unchecked consumption of groundwater. Without revenue coming in from the water tax since 2011, the cost of producing drinking water is also not recovered, making the system unsustainable in the long run.


Kolkata’s ground water is contaminated with arsenic, heavy metals originating from industrial discharges, and organic matter originating from domestic sewage. Its wetlands too are threatened by encroachment, siltation, changes in land use patterns, industrial effluents and sewage inflow.

To make matters worse, the city has no sewage treatment plants (STPs) within its municipal area. Its three plants are located outside its municipal limits at Bangur, Garden Reach and Bagha Jatin.

Only 172 MLD of the total 705.86 MLD of the sewage generated in the city is being currently treated, as per a study done by ENVIS, Environmental Information System.


As per the 2011 census, Kolkata has a total population of 4.4 million.

By 2025, Kolkata’s groundwater demand may rise about 25% from the present demand of around 310 million litres every day.

The city’s demand for water and its population are growing at a steady rate. Its wetlands, however, are not.

This means that in a few years, there will be even more pressure exerted on the city’s finite and (already) over-exploited resources – pushing Kolkata into a severe water crisis.

The city and its people, therefore, need to take conscious measures in order to ensure that Kolkata does not run out of water.


East Kolkata Wetlands – spread over an area of 125 square kilometers – were designated as “Wetlands of International Importance” under the Ramsar Convention on 19 August, 2002.

As measures such as these are underway to conserve Kolkata’s wetlands and to protect the rich biodiversity supported by them, there is still hope that Kolkata – with the help of its wetlands – can defend itself against floods, become capable of combating climate change and bring its people out of the current water crisis.

However, it is not only the government or NGOs that play a crucial role in deciding the fate of Kolkata’s wetlands.

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Subhash Sarovar

Subhash Sarovar is a lake located near Beliaghata, in Kolkata. It is a popular bird watching and tourist spot.

The lake, however, has undergone a long period of neglect and is suffering from an increasing population of the Alligator Gar – a fish that can grow up to 8 feet and that eats almost every other fish in the lake. The Gar has no natural enemies to keep its numbers in check and may, therefore, become a threat to the natural ecosystem and biodiversity of the lake. According to experts, the fish is a non-native species and is generally released into water bodies by smugglers. To tackle the problem, experts have already been called for help.

In a first of its kind joint venture between the Kolkata Improvement Trust (KIT) and West Bengal Tourism Development Corporation (WBTDC), the lake area would be converted into a tourist destination, for picnickers and anglers.

East Kolkata Wetlands

East Kolkata Wetlands are a complex of natural and human-made wetlands lying east of the city of Kolkata. The wetlands cover 125 square kilometers and include salt marshes and salt meadows, as well as sewage farms and settling ponds.

Kolkata is heavily reliant on these wetlands since they:
- Produce 10,000 tonnes of fish each year
- Provide 40 to 50% of the green vegetables available on Kolkata’s markets.
- Act as a strong flood defense
- Provide livelihood support to a large, economically underprivileged population of 20,000 families, through wetland products such as fish and vegetables
- are used to treat large quantities of Kolkata’s domestic sewage

These wetlands are on the ‘List of Wetlands of International Importance’ under the Ramsar Convention since they support an amazing number of species and provide livelihood to the numerous villages located around them.