Chinese state-run media say a third of China's vast land mass has been hurt by acid rain caused by the emissions of factories and power plants.

The official Xinhua news agency cites a parliamentary pollution report released Saturday, which says emissions of sulphur dioxide, the chemical that causes acid rain, are two times higher than safe levels.

Sheng Huaren, the vice chairman of the parliamentary standing committee, says China's factories discharged some 25 million tons of sulphur dioxide last year, up 27 percent from 2000. He says the resulting acid rain is threatening China's soil and food safety.

China is struggling to balance its booming industrial growth with environmental protection. A series of chemical spills has cut off drinking water to millions of people over the past couple years, and air pollution is a constant problem in many cities.

Some information for this report was provided by AP and Reuters