Expedite works to curb sewage flow into Thenpennai, NGT tells Karnataka

CHENNAI: The southern bench of the National Green Tribunal (NGT) has directed the Karnataka government to expedite works to arrest the discharge of sewage and industrial effluent into the Thenpennai River, citing the arrival of the northeast monsoon in Tamil Nadu.

The bench also instructed Karnataka to file a report outlining the measures proposed to address the discharge into the river.

While hearing a suo motu case on letting sewage and industrial effluent into the river, the bench comprising judicial member Justice Pushpa Sathyanarayana and expert member Satyagopal Korlapati noted an assurance made by the Karnataka government that the construction of sewage treatment plants (STP) would be completed by the end of December 2025.

“Considering that over five months remain until the end of December 2025 and the monsoon is approaching in the State of 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,” the bench observed.

During the hearing, the Karnataka government filed a report stating that the Bangalore Water Supply and Sewerage Board has proposed to construct 10 new STPs with a proposed capacity of 313 MLD and obtained administrative approval for 4 STPs that are in the tender stage. For the construction of the remaining 6 STPs, an estimate of Rs 1200 crore is prepared, which will commence shortly.

The report also stated that there are 531 industries and organisations located within the catchment area of the river, of which 11 are non-compliant with the norms.

“The report finally stated that the polluted river stretch of the Dakshina Pinakini River is under consideration for rejuvenation, and a report is being prepared by the Deputy Commissioners of Bengaluru Urban and Bengaluru Rural Districts in consultation with the stakeholders and will be submitted in two months,” the report added.

Meanwhile, the water resources department of Tamil Nadu pointed out that before descending the interstate border into Tamil Nadu, the overflow water from Bellandur and Varthur Lakes carries the domestic sewage of Bengaluru into Thenpennai River, causing frothing of the river stretch from the Tamil Nadu border up to Kelavarapalli dam.

Also, the Negotiation Committee for the Thenpennai River water dispute inspected in June 2024 and found that the water in the dam was polluted, blackish in colour, foamy, and emanating a bad odour.

The bench ordered the Karnataka government to control the industrial pollution and commence the bio-remedial sewage treatment process. The Government of Tamil Nadu will take up the bio-remedial measures after getting a feasibility report once the industrial pollution is curbed.