Bengaluru: The Karnataka State Pollution Control Board (KSPCB) has blamed surface water, sewage from unorganized sectors for polluting the lakes, which ultimately leads to incidents of fish kills, while admitting that lack of thaw has led to reduction in the water-bearing capacity of the water bodies.
The KSPCB was responding to a notice from the National Green Tribunal regarding media reports on incidents of fish kills in Bengaluru lakes. The court had sought the Board’s response on the actions taken to prevent pollution.
In response, Environment Officer K Sudhakar said that the lake water in Bengaluru was “usually” polluted due to inflow of surface runoff and due to discharge of sewage and sewage from unorganized sectors. He said areas where sewage treatment plants (STPs) have not been set up by the Bangalore Water Supply and Sewerage Board are particularly contributing to the pollution load.
“Lack of periodic thawing of lakes results in reduced water-holding capacity. The entry of sewage into lakes, under such circumstances, results in excessive depletion of dissolved oxygen levels and also increases turbidity, which is the main cause of fish kills in lakes,” it said.
The officer said pollution levels in lakes naturally decrease when there is “proper rainwater runoff”, further stressing the need for desilting.
He said industries, apartments, commercial complexes, hotels, hospitals and other institutions covered by the consent mechanism have been told to set up their own treatment plants and use the treated water within the premises and in construction activities.
Stating that the fish kill incidents have prompted immediate response from the KSPCB, the officer said the government was also looking into the pollution of the lakes following an order by the Karnataka High Court. A committee headed by the chief secretary was looking into the pollution issue, he added.
