Thousands of fish were seen floating on the surface of the river at several places, officials said.
The incident led to panic and wild speculation that the river water could have been poisoned. Many people were seen recording the incident on their mobile phones.
The administration has assured people and urged them not to panic. They have collected water samples and sent them for tests.
Mr Rasheed in a statement said a technical team has visited the various spots and suggested further tests. "The administration is seized of the matter and working to ensure that no untoward incidents occur."
Get Breaking news, live coverage, and Latest News from India and around the world on NDTV.com. Catch all the Live TV action on NDTV 24x7 and NDTV India. Like us on Facebook or follow us on Twitter and Instagram for latest news and live news updates.