Reports in China have said that the river started to turn red at around 6am last Thursday morning, before it finally reached a deep, blood-red colour.

Residents have also claimed that they could detect a strange smell in the air. 

The locals are said to be baffled by the event, with local fishermen complaining that they can no longer fish in the river and that even if they could, who would want to eat the catch.

China Radio International reported that environmental officers took samples to try and determine where the colour change came from.

It is suspected that people may have dumped red pollutants or artificial colouring into the water.

It has also been reported that a paper manufacturer, food coloring company and clothing-maker are situated along the river but the incident is still under investigation by police.