NGT recommends steps to prevent fish kill in Periyar

The National Green Tribunal (NGT) has recommended steps to prevent future fish kill along the Eloor–Edayar industrial stretch of the Periyar by asking the authorities to ensure better management of river flow, strict regulation of industrial waste, and control of all forms of pollution from industrial sources.

The Southern Bench of the Tribunal, in an order dated July 2, 2025, directed the Kerala State Pollution Control Board (PCB) to submit the reports of various agencies that investigated the mass fish kill in the industrial stretch on May 20, 2024, before the Kerala High Court, for consideration in the pending writ petitions seeking a permanent solution to the frequent fish kill downstream of the Edayar industrial stretch.

The Tribunal had taken suo motu cognisance of the incident based on a report titled “Another mass fish kill in Periyar River in Kerala after suspected effluent release,” published in The Hindu on May 21, 2024.

The Tribunal, while disposing of applications seeking action against pollution in the Periyar, observed that fish kill was primarily caused by a combination of sudden changes in water flow and industrial pollution.

It is generally alleged that opening the Pathalam regulator shutters results in low oxygen levels and the accumulation of organic matter. Citing reports from Kerala University of Fisheries and Ocean Studies and the PCB, the order stated that the primary allegation was that the sudden release of water through the shutters caused a rapid increase in flow when the river was already carrying a heavy load of organic matter and pollutants.

The Eloor–Edayar industrial belt also discharged waste into the river, significantly contributing to the overall pollution load, including elevated levels of ammonia, hydrogen sulphide, and other chemicals intolerable to fish. The order said that in 2024, there were recurring incidents of mass fish kill in the Periyar, often linked to the opening of regulator shutters and the resulting deterioration in water quality.