These effluents get mixed with drinking water through leaks in nearly a century-old water pipelines in the area. A doctor of a local nursing home said diarrhoea is quite common in the area and locals are susceptible to stomach ailments.

Just a week before the outbreak of diarrhoea in Ward 135, there was an outbreak in adjacent Ward 138, leaving nearly 60 people affected. Since the outbreak in Ward 138 was not attended in time, the contamination spread in other wards, including 134, 135, 136 and 138. The Kolkata Municipal Corporation, however, hushed up the matter and did not set up any medical camp in the area. Significantly, Mayor Bikash Ranjan Bhattacharya appeared clueless about the outbreak and its cause.

“We are yet to find the cause of the contamination and are replacing the damaged pipelines. But the water contamination in ward 138 cannot be stopped until the chemical factories are removed from there,” said Mrinal Mondal, MMiC, water supply.

Incidentally, sewer lines and drinking water pipelines are laid very close to each other in the area and even a slight leak in the pipeline may cause a severe water contamination.

According to a senior official of the West Bengal Pollution Control Board (WBPCB), the untreated effluents released by the factories contains various acids and get mixed with the soil and percolate deep in the soil.

Sometimes the effluents also reach the underground water sources and contaminate water of tube wells, he added.

Mondal said all the factories are illegal and do not have a trade licence of the KMC. “We cannot shift the factories from the Garden Reach area. This is the job of the administration. I will meet the police chief soon so that action can be taken against these factories,” added Mondal.

The WBPCB has served several notices to the factory owners asking them to treat the effluent before releasing into drains, but to no avail.