Calcutta, now known as Kolkata, has a history of nearly 350 years and a strong colonial past. Job Charnock, the British administrator of East India Company who is traditionally regarded as the city’s founder dates as far back as 1690. Starting from a humble beginning of three connected villages off river Hooghly, a swampy, marshy and malaria-ridden British trade post in Bengal, it rose to prominence of a city fashioned by the British much after London and then a metropolis, 13th most populous in the world with a queer mix of seemingly opposites – poor and rich, shanties and mansions, old and new. This also happens to be the place where I lived my entire life, which is hardly historical.

When Calcutta began its growth as a city, it expanded north-south along the levees of river Hooghly, also known as Ganges or Ganga in local parlance. During the last century and as the British left India the city started a east ward expansion to cope with the huge pressure of municipal population, a population that not only received influxes of people from all around the country for basic livelihood but also repeated influxes of the refugees from the neighboring Bangladesh (formerly East Pakistan), the recent of such influxes being during 1970-71 (war of liberation for Bangladesh).

It was not unknown to the early planners of the city that expansion towards east was not a favorable option because the natural drainage slope of the city of Calcutta is towards east, away from Hooghly River and the natural drainage channel remained the river Bidyadhari in the east. Moreover the eastern fringe of Calcutta, just 5 km from its center, is a wetland with numerous shallow ponds, marshy lands, and a natural catchment for surface run-off of the city before the final drainage through river Bidyadhari. Despite this knowledge, just to cope with the mounting developmental pressure, scarcity of living area and space, a satellite Salt Lake City came up east of Calcutta in the 1960s. The cosmopolitan Calcutta seemed to understand the environmental value of the east Calcutta wetlands quite early and in a landmark public interest litigation between an NGO ‘People United for Better Living In Calcutta (acronymed as PUBLIC) vs State, Calcutta High Court ruled in favor of PUBLIC stating that public opinion should count in the development and planning of the city.

This historical background is a necessary description because, only recently it came into popular notice that something remarkable had been happening in the eastern part of Calcutta for decades, maybe a century or so. East Kolkata Wetland (EKW) is a human developed (without conscious planning and just out of common wisdom) series of many shallow fish ponds (locally known as Bheris) which, taken as a whole, is the world’s largest sewage fed fish pond system. It contains a non-urbanized population quite close to Calcutta, who, by sheer experience and innovation has devised a multiple use ecology that is a unique natural waste recycling system which is self sustained with its own economy and an example of a ecology maintained and guarded quite unconsciously long before environmental concepts came to exist.

What it does is basically this.

East Kolkata Wetlands, measuring roughly 12,500 ha and having 150,000 inhabitants receive about 1000 million liters of urban sewage per day and collect it in shallow stilling ponds (only about a meter or two deep) where abundant sunlight, or more correctly the UV radiation kills the pathogens in it. The supernatant liquid is then channeled into fish ponds where endemic varieties of fish feed on the nutrients ultimately rendering the liquid safe to be discharged into the Bidyadhari River. The fish stock is enough to sustain the wetland population economically as all the fish is easily supplied to local markets of the city where there is a huge demand. The system is going on for nearly 200 years without any reported case of health hazard. The estimated annual fish yield from EKW is about 13,000 tons (one third of city’s annual consumption). Some 150 tons of fresh vegetables are harvested by small scale plots irrigated with the waste water from the fish ponds, which again finds an easy market in Calcutta. The whole system has come to be known as ‘kidney of Calcutta’ with no parallel in the world, a name earned for the remarkable way the local wisdom created a partly natural, partly artificial waste recycling and treatment system, that if attempted through modern technology would have cost 90 million dollars per year. EKW is also a bio-diversity store house with over 100 plant species, rare mammals including the marsh mongoose, the small Indian mongoose, the palm and Indian civets, and the threatened Indian mud turtle. There are also some 40 species of birds, both local and migratory, which include kingfishers, grebes, cormorants, egrets, terns, eagles and sandpipers. Most importantly, like all wetlands, EKW acts a carbon sink and helps reduce green house gas emissions. The East Calcutta Wetlands were designated a “wetland of international importance” under the Ramsar Convention on August 19, 2002.

As the city of Calcutta expanded, the municipal solid waste (MSW) was started to be dumped in one part of the EKW and it magnificently went on to convert and recycle it much like the sewage water. The daily MSW of Calcutta, estimated at 2,500 tons is received here, segregated and composted to organic manure that partly helps the 150 ton per day vegetable and an additional 15,000 tons of paddy per year.

The East Kolkata Wetland and waste recycling region serves to:

(a) absorb and treat in the most efficient, economical and natural way the huge volume of sewage and wastewater and urban solid and air wastes generated by the Kolkata city – at no cost to the city but with much gain.

(b) fulfill substantially the requirement of fish, vegetables and food-grains in the city.

(c) absorb the pollution from, and purify the air that the citizens breathe.

(d) absorb and pass down to downstream creeks and the sea the flood waters that the monsoon downpours bring down on the city.

(e) provide a habitat for a variety of flora and fauna and living organisms endemic to wetlands.

(f) provide the food chain and waste-to-wealth recycling so unique and essential to this city.

(g) maintain the micro climatic condition of the region.

(h) maintain the delicate ecological balance in a fragile environment and eco-system.

(i) provide livelihood support for thousands of local villagers who also have the unique skill of using wastewater to grow fish and vegetable and thereby help sustain a stable urban fringe.

All this at no extra cost and completely indigenously.

Doesn’t it sound almost too good to be true? There is bad news for this Ramsar site and like everywhere it is threatened by over urbanization, increased tail-pipe emissions containing heavy metals, real estate encroachments, increase of industrial (particularly tannery) wastes in the city sewage. Also, it seems that EKW is losing to the mammoth pressure of city garbage, which has pushed the delicate ecology of EKW to its limit. If EKW is Calcutta’s kidney then we may need dialysis soon. Following is a video by SAFE (South Asian Forum for Environment):

[Image courtesy: Island Press]

About the Author


2 Responses to A city on renal failure

  1. Pabitra says:

    Thanks Npong. You are welcome. Bring your friends too!

  2. npong says:

    I am happy you have finally gotten your voice. Please speak i am listening to you.
    the design of the site is beautiful and so far you have spoken on the city of rinal failure.
    i would be here everyday to learn more from your great works.
    What an incredible creativity and innovation!
    Bro keep it up

Leave a Reply