Courts across the Guangxi Zhuang autonomous region sentenced 13 people on Tuesday stemming from charges of polluting a river in the region with heavy metals last year.

Three of those jailed were environmental inspectors who failed to perform their duties and allowed plants to dodge pollution inspections. The plants discharged industrial effluents containing cadmium into the Longjiang River from April 2011, the courts said.

The Dahua county court in the city of Hechi sentenced Zeng Juefa, former deputy director of the city's environmental protection bureau, to four-and-a-half years in prison for delinquency and taking bribes.