More than 9 hundred dead pigs have been pulled out of a river near Shanghai, China, and Chinese environmental officials are trying to determine why this is happening.

The pigs are turning up floating and washed up along side an up-river portion of the Huangpu River where Shanghai draws its drinking water supply.

They say that drinking water quality is acceptable, but they’re beefing up inspections to make sure.

There are no reports of animal disease epidemics up stream.