Authorities in South China's Guangdong province said on Sunday (18 March) they were working to clean oil slicks on a river that might threaten the water supply to a city of 4 million.
A water company in Jiangmen reported on Saturday afternoon that a large expanse of oil was found floating near the source of the city's two waterworks on the Xijiang River, an official with the city government's information office said.
The oil, possibly diesel, was believed to have spilled from a ship that sank in the river late on Friday, the official said.
Cleanup and pollution-control operations began Saturday afternoon, and the government said that repeated water quality checks indicate that tap water in Jiangmen was safe to drink.
The government pledged it would further clean the spill and monitor water quality. An investigation is under way.
Xijiang River is a major tributary of the Pearl River, the third longest river in China and a pivotal waterway that runs across the economic heartland of Guangdong.