Lakes upstream of Hesaraghatta are being polluted by sewage from Doddaballapur and Bashettihalli, the KSPCB has found.
It sought three months to inspect the sewage network and find out the full extent of the pollution.
The board presented a status report before the National Green Tribunal (NGT) in which it identified Nagarakere, Majarahosahalli (Chikkatumakuru), Doddatumakuru, Veerapura and Muttur lakes in and around Doddaballapur as polluted.
Acting on a petition by environmental activist Girish N P that drew its attention to environmental violations, including the sewage flow into the lakes and a sewage line installed in the lakebed, the NGT ordered KSPCB to probe the issue.
Acknowledging that untreated sewage is being released into Majarahosahali lake, also known as Chikkatumakuru lake, the board said sewage from Doddaballapur is taken to an oxidation pond before being discharged into the lake, while sewage from Bashettihalli is directly released into the lake.
The board cited the Assembly polls as the reason for seeking three months’ time. According to the map provided in the revenue department’s Dishank app, Chikkatumakuru lake is linked with a network of other waterbodies that are connected to Hesaraghatta lake.