Around 70 percent of the tributaries of the Huaihe River, the supplier of water to one sixth of the country's 1.3 billion population, are seriously polluted, according to an annual environment monitoring report issued by the Environmental Protection Administration of east China's Anhui Province.

The overall water quality of the mainstream is described as lightly contaminated. Most of the pollutants are ammonia and nitrogen, the report says.

In 1994, China launched a campaign to clean the water of the Huaihe River. By the end of 2005, 62.7 percent of the projects listed in the campaign were completed but with limited effect. The water-cleaning action "achieved less than expected result, and pollution in the tributaries is still severe, if not worse," said Pan Yue, deputy director of the State Administration of Environmental Protection.

Water from Huaihe's tributaries, which carry 60 percent of the total water resources of the river, are too polluted to supply even industrial production and irrigation, let alone drinking.

The State Administration of Environmental Protection has ordered local governments to adjust the industrial structure, arrange agricultural and industrial production based on the river's capacity and push forward the emission licensing system.

The Huaihe River flows through four central and eastern Chinese provinces - Henan, Anhui, Shandong and Jiangsu - and is located between the country's other two major rivers, the Yangtze and the Yellow rivers.