District officials said the fish could have died after molasses leaked from a sugar factory into the river near Beas town, 40 km from Amritsar.
"According to experts, molasses, which leaked from a sugar factory here in Beas, mixed with the river water and reduced the oxygen levels. This led to the death of fish. We have collected samples of the water and will get them tested," Sangha told the media.
The dead fish were taken out of the river.
Officials said that the molasses, which had turned the colour of the river water to brown, was spread in an area of over 30 km.
The PPCB has ordered the shutdown of the sugar factory.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)