The report mentioned the sewage in Bellandur and Agara lakes, algae bloom in Varthur lake(in the picture) as well as pathetic condition of Yele Mallappa Shetty lake.
Credit: DH photo
Bengaluru: The National Green Tribunal has directed Karnataka to immediately stop the industrial effluent from flowing into Dakshina Pinakini ('Pennaiyar' and 'Thenpennai' in Tamil Nadu), and the Kelavarapalli dam that directly irrigates 9083 acre of agriculture land.
The NGT's southern zone bench of Justice Pushpa Sathyanarayana and expert member Satyagopal Korlapati was hearing a suo motu case registered following media reports of toxic foam in Hosur's Kelavarapalli dam.
The order came after Karnataka sought time till December 2025 to check the flow of waste water by constructing 10 new STPs.
Karnataka's report said that of the 531 industries in the catchment area, 272 complied with rules, 58 were discharging sewage into the underground drainage, 27 were non-operational while 11 were non-compliant.
Site visit uncovers pollution
However, a site visit by a joint committee showed that Karnataka was releasing highly polluted water into Tamil Nadu as well as the slow progress in cleaning up the mess in Karnataka's lakes.
The Tamil Nadu government, however, stated that the river traversing through minor irrigation tanks in Chikkaballapur, Bengaluru Rural and Bengaluru Urban districts was polluted with both industrial effluents and domestic sewage.
The report mentioned the sewage in Bellandur and Agara lakes, algae bloom in Varthur lake as well as pathetic condition of Yele Mallappa Shetty lake.
Red and orange category industries
Further, the Tamil Nadu government said it can take up bioremedial solutions but Karnataka has to stop dumping industrial effluents into the river. "Effluent from Red (highly polluting) and Orange category industries at the river catchment in Karnataka state have to be completely treated or stopped from letting into the river to operate bio-remedial measures effectively to treat the sewage," it said.
Immediate action amid approaching monsoon
The tribunal noted that only five months remained until the end of December 2025 and the monsoon was approaching in Tamil Nadu.
"It would be appropriate for the state of Karnataka to take immediate steps to address the discharge of industrial effluents and control the mixing of sewage into the Thenpennai river, pending the completion of the proposed sewage treatment plants (STP), as outlined in their report," it said.
As Karnataka sought a month's time to respond to the report by Tamil Nadu, the NGT sought a report outlining the measures proposed to check flow of industrial and domestic waste into the river pending the construction and commissioning of the STPs.