The head of China's environmental protection agency has resigned, according to state news agency Xinhua.
Harbin did not have a mains water supply for five days
No reason was given for Xie Zhenhua's resignation, but it follows a chemical leak which forced authorities in the city of Harbin to cut off its water.
Environmental officials in Jilin province, where an explosion caused the leak, have also been criticised for failing to act more quickly.
Harbin's water was declared safe to drink earlier this week.
The leak of the chemical benzene was caused by a blast at a chemical plant on 13 November, in the north-eastern province of Jilin.
It flowed into the Songhua river and led to a five-day shut-off of the water mains in nearby Harbin.
The State Environmental Protection Administration (Sepa), which was led by Mr Xie, said on Thursday that it did not receive notification of the spill for five days.
Mr Xie was replaced by Zhou Shengxian, former director of the State Forestry Administration, Xinhua said.
The spill is now flowing towards Russia. It was lengthening and slowing down as it did so, the Associated Press reported on Friday.
It is expected to reach Russian territory in the coming days.