Environmental authorities in a city in eastern China have hit petrochemical giant Sinopec with a penalty reported to be 90,000 yuan ($14,670) for causing air pollution.

The rare move sets a good example in regional governments' battle against large State-owned polluters, experts said.

The Environment Protection Bureau of Anqing, Anhui province, made the decision after a branch of Sinopec, Asia's largest refiner, was found late last month to have discharged excessive amounts of polluting materials in the city of 6.2 million people.