On Sunday, thousands of fish were found dead in the Sri Subramaniya Swamy temple tank in Thiruparangundram in Madurai.

The villagers suspect that the water tank may have been poisoned by rival groups over a dispute about fishing rights. However, the environmentalists have a different take on it.

“It could either be because the fish are not able to acquaint themselves to the weather conditions or because of the increase in pollution in these tanks,” said Tamil Dasan, part of Naanal Nambargal, an organization which works towards environmental issues.

“Also their food chains are disrupted as many of these tanks do not have water plants,” he added, observing that such fish deaths are becoming common in Madurai’s public tanks.

K Shativel, Founder of Rainstock, a water conservation enterprise, also said that sudden weather changes and pollution are likely causes of fish deaths. “At times when it is too hot and it suddenly starts raining, that can adversely affect the fish. Other than that, sewage water getting mixed with tank water can also be one of the reasons for the death of the fish. Poisoning of these tanks might also be the reason behind it.”

Madurai collector K Veera Raghava Rao told NDTV, “We have sent water samples for testing. Carcasses have been removed to prevent spread of diseases, and based on the reports we will decide the next course of action.”