Something unusual and deeply disturbing is unfolding on River Kosasthalaiyar near Chennai. The river, which fishing villages including Nettukuppam, Thazhankuppam and Mugathuvarakuppam have depended on for generations, is now blanketed with dead fish, spanning multiple species including silver belly fish, croakers, sea catfish, threadfin bream and goatfish.
Fisherfolk say they have never witnessed anything on this scale before, in terms of both the number of dead fish and the variety of species affected.
What locals suspect
Fishing communities say this isn’t the first time they’ve seen fish deaths in these waters. In the past, they claim, extreme heat and thermal discharge from nearby industrial activity occasionally caused smaller fish kills. But they say this time is markedly different, and they suspect chemical waste is being discharged into the river.
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They aren’t alone in that suspicion. Researchers from the Indian Council of Agricultural Research have reportedly flagged industrial effluents and domestic sewage as likely contributors. Earlier studies had already found industrial units along this stretch releasing large volumes of effluent carrying heavy metals directly into the estuary.
So far, no government official has visited the affected villages. That silence pushed fisherfolk onto the road on Sunday (August 16), where they blocked the Thazhankuppam-Ennore Expressway, demanding that someone in authority show up and respond to what’s happening in their water.
Not an isolated incident
This isn’t the first ecological disaster Ennore has lived through, and not by a long distance.
“The oil spill, the gas leak, the repeated fish kills, these are not isolated incidents. They’ve been happening from the 1970s onward, when the first industries were set up in Manali and Ennore,” Nityanand Jayaraman, writer and activist with the Save Ennore Creek Campaign, told The Federal.
“Is there something fundamentally wrong? Absolutely. This shows there is no such thing as environmental governance. Because if there were, our rivers would be running clean,” he added. “There isn’t a single river in Tamil Nadu that’s actually clean, and that shows every institution meant to ensure accountable governance has failed.”
Disaster of 2023
Rewind to December 2023. Just before midnight on December 26, an undersea pipeline belonging to Coromandel International near Ennore creek was damaged after heavy boulders shifted during Cyclone Michaung, and the damage went unnoticed. The result was a massive ammonia leak, releasing more than 67 metric tonnes of ammonia into the air in just 15 minutes.
Watch | Coromandel’s toxic legacy is slowly killing Ennore residents
Residents had no warning. People rushed out of their homes in the middle of the night, choking, their eyes burning, struggling to breathe. More than 60 people, including many children, were hospitalised, and several required oxygen support for days afterwards.
The Tamil Nadu government ordered the plant to shut temporarily. Residents and environmental groups pushed for a permanent closure. Still, by May 2024, the National Green Tribunal cleared the company to reopen, on the condition that it follow pollution board guidelines and secure safety clearances from multiple authorities.
Oil games
The ammonia leak wasn’t the only disaster that year. Just weeks earlier, floodwaters from Cyclone Michaung had overwhelmed Chennai Petroleum Corporation Limited’s refinery, sending an estimated 24,000 litres of crude oil into the Buckingham Canal. From there, it spread into the Kosasthalaiyar river, Ennore creek, and out into the Bay of Bengal, coating boats, shredding fishing nets and killing marine life across the region.
“We’ve not been hearing what the people have been saying for the last thirty to forty years. They’ve been saying Ennore is already not fit for living. The creek is already not healthy enough for fish and other life to thrive. The birds have disappeared. I think there is sufficient proof for people to take action, if they had the political will. I think the reason Ennore is being sacrificed is because it’s predominantly populated by marginalised communities, and this is a case of environmental casteism. There’s no other word that can describe it,” Jayaraman said.
Government faces flak
An oil spill. A gas leak that nearly asphyxiated an entire community. And now, in 2026, a mass fish kill that fishermen say they’ve never witnessed on this scale.
The Vijay government now finds itself under direct scrutiny, with protests showing no sign of easing. This comes at a moment when the state is actively courting new industries and factories into the region, turning Ennore into an early test of whether the government’s growth push can coexist with the very communities and ecosystem it keeps failing.
“What we are seeing is a repeat of the same thing, it’s just the people have changed, the conditions on the ground have absolutely not changed. We might say that the government is very new. I’m saying this is a chance for you to take action. Clean up the Ennore Creek. This is something that I said in 2022. The DMK government did nothing. You’ve been here already for close to four months and you haven’t taken any initiative to improve the situation in Ennore. On the contrary, you’re increasing the number of industries there, you’re increasing the power plant capacity in that area, and that is not something that shows that you are for change. You’re continuing with the same disastrous model,” Jayaraman said.