"Various chemicals have been detected in some rivers, lakes and inshore waters, as well as in animals and human bodies in recent years," the ministry said.

"Toxic chemicals have caused several environment emergencies linking to water and air pollution. Drinking water crises hit many regions while 'cancer villages' and other severe cases of health and social problems emerged in some other regions," the ministry said.

According to the plan, sources polluting underground water will be under tight supervision by environmental watchdogs by 2020.

Shallow underground water in China has been severely polluted and the situation is deteriorating rapidly, with water quality data in 2011 showing that 55 percent of underground supplies in 200 cities was of bad or extremely bad quality, according to the Ministry of Land and Resources.

A review of underground water carried out by the ministry from 2000 to 2002 showed that nearly 60 percent of shallow underground water was undrinkable, the Beijing News reported yesterday.

Some reports in the Chinese media said water pollution was so severe in some regions that it caused cancer in villagers and even led to cows and sheep which drank it to become sterile.

In the latest pollution scandal, chemical companies in east China's Weifang City were accused of using high-pressure injection wells to discharge waste sewage more than 1,000 meters underground for years, seriously polluting underground water and posing a cancer threat.

The government of the city is offering 100,000 yuan (US$16,000) to anyone who blows the whistle on companies illegally discharging waste underground. So far, no companies have been caught for polluting the environment.