China's largest pipeline project to purify the sewage of the Yangtze and Jialing Rivers has gone into construction in Chongqing, a municipality directly under the Central Government, in southwest China.

Sources said that about 700 million tons of untreated waste water is discharged into the Yangtze River and its branch Jialing every year, which has seriously polluted the river valleys and posed a vital threat to the ecological environment of the Three Gorges area.

Some state departments together with the Chongqing Municipal government are taking active roles in dealing with the sewage pollution in the area.

In the first phase of the sewage treatment project that is planned to be completed in the year 2004, a 92-kilometer underground pipeline network will be built up to collect daily household waste water. Two sewage plants with the daily processing capacity of 800,000 tons and 400,000 tons each will also be set upto purify the sewage water transported by a main 72-kilometer-long pipeline.

The World Bank and the Chinese State Development Bank (SDB) respectively will provide 40 percent and 25 percent in total loans of 2.7 billion yuan (more than 310 million US dollars) to the project, and Chongqing Municipality will raise the remainder of the money.

The 6,300-kilometer Yangtze River, China's largest river and the third largest in the world, flows past Qinghai, Tibet, Yunnan,Sichuan Hubei, Hunan, Jiangxi, Anhui, Jiangsu and Shanghai, where it empties into the East China Sea. Important cities along the way are Chongqing, Wuhan, Nanjing and Shanghai.

The Jialing River, a main waterway in southwest China's Sichuan Province, is one of the important tributaries of the Yangtze. It stretches for 1,000 kilometers through 14 counties in the central hilly area of the province.