Residents noticed the dead fresh water fish in the river in Punjab's Beas town, about 40 km from the state capital of Amritsar, and informed the authorities.
Officials, including Deputy Commissioner of Amritsar Kamaldeep Singh Sangha, and experts from the Punjab Pollution Control Board (PPCB) and wildlife department visited the site to take stock of the situation.
He added the PPCB had ordered the closure of the factory.
Molasses leakage also changed the colour of the river water to rust brown.
"We have also collected water samples and will get them tested to ascertain if something else may also have been there," said Sangha.
Fresh water from the Pong Dam was released into Beas to flush out the pollutants.
"With the release of fresh water, the situation is much better now," Sangha said.
Authorities have also issued an advisory asking residents not to eat or sell the dead fish.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)