About 900 pigs have been found dead floating down the Huangpu river near Shanghai.
An inquiry has been launched by China's agriculture commission but no evidence has been found so far as to how or why the pigs were dumped in the river.
BBC said that authorities are monitoring the water for diseases.
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Residents of Shanghai use the river as a source of drinking water, said China Daily, and as of Sunday not all the pigs had been retrieved.
This is just the latest in a series of environmental disasters in China, which include lead poisoning, acid spills and fluoride leaks, reported Bloomberg.