A Zhejiang entrepreneur has offered 200,000 yuan ($32,000) to any local environmental protection official willing to swim in a filthy local river for more than 20 minutes.

Jin Zengmin, chairman of Hangzhou's Maoyuanchang Eyeglass Ltd Co, said he "dared" the city's environmental chief to jump into the un-named river, which flows through the Xianjiang neighborhood of Rui'an city.

Referring to it as "the river I used to swim in when I was little" and the same used by his mother to wash the family's clothes, he claimed that residents have suffered from unusually high cancer rates as a result of pollutants in the water.