The mysterious death of thousands of fish in southwest China's Chongqing Municipality may be connected with chemical pollution, an environmental authority said on Wednesday.

Thousands of fish were found floating in Fujiang River in Tongnan County on Monday, triggering scare among local villagers. [Chongqing Times]

Thousands of fish were found floating in Fujiang River in Tongnan County on Monday, triggering scare among local villagers.

"The massive fish death may have been caused by the yellowish industrial waste water discharged by chemical plants alongside the river," a spokesman for the Chongqing Municipal Environment Protection Bureau said at a press conference.

Water quality tests in the river showed the chemical oxygen demand slightly exceeded the normal level, he said.

He said the local government has launched an investigation to find out the source of pollution.