Some 100 tons of benzene were dumped into the Songhua River, a major tributary of the Amur, on 13 November after a huge explosion at a chemical plant in Jilin province, some 380 kilometers up river from Harbin.
Public water supplies to Harbin were cut on 22 November as the government scrambled to bring massive shipments of bottled water into the city to avoid a health crisis.
China's official Xinhua news agency quotes city officials as saying that the city will launch a three-level color warning system to gauge water quality to ensure the health of Harbin's residents.
(AP/AFP)