A statement by the city government in Hebei province said the water was cut-off after an accident in the neighboring Shanxi Province where industrial pollutants poured into the upper reaches of the Zhanghe River.
The Shanxi provincial government said a flexible tube rupture at a chemical plant in Changzhi City caused aniline to leak into the Zhuozhang River, the upper reaches of the Zhanghe River, on December 31. The statement did not specify the quantity of the leakage.
Aniline is a toxic chemical widely used as precursors in the manufacture of pigments, herbicides and other chemicals. Authorities in Shanxi said they received the report on Saturday, and that an emergency response had been initiated to stop the leak and clean up the pollutants.
A statement from the Changzhi City said the accident had not caused casualties so far, and that water quality in the Zhuozhang River was improving.
They said cities along the river, including Handan and Anyang City in Henan Province, have been warned to be on alert, state run Xinhua news agency reported.
The city of Handan has cut off its water supply from Yuecheng Reservoir located on the river and switched to another underground water source.
Air and river water pollution is a common concern in China, which has made big strides in manufacturing industries in the last three decades causing heavy damage to environment.