Kerala State Pollution Control Board (KSPCB) officials on Thursday said inflow of brackish water must have killed fish in Chalakudy river on Wednesday.

Local people saw dead fish turning up along the banks of the river from Thaikkodam to Annamanada, and at Cheruvalur and Pulikkakadavu.

Activists alleged that disposal of untreated effluents from Nitta Gelatin India Limited’s plant at Kathikkudam into the river had killed the fish. They gheraoed chief environmental engineer T.A. Thankappan while he was inspecting the river on Wednesday. He was made to remain in a boat in the middle of the river for about five hours. The District Collector and the police intervened to solve the problem.

According to reports of the KSPCB, effluents from NGIL are not suspected to have killed the fish. “A shutter at Kanakkankadavu in Ernakulam district to regulate brackish water was opened. The inflow of brackish water must have killed the fish. Saline water kills freshwater fish,” said Mr. Thankappan. Samples of water from areas where the dead fish turned up have been sent to KSPCB’s Central Laboratory at Gandhi Nagar in Kochi for tests. “A report will be available within a week. Only the tests will confirm the cause of death,” Mr. Thankappan added.