The water quality of tributaries at the upper reaches of the Yangtze River, China's longest, has been improving, according to the Sichuan Provincial Environmental Protection Bureau.

Last month, the water quality was upgraded to level two of the national standard in the Jialing, Minjiang and Tuojiang rivers in southwest China's Sichuan Province.

Eighty-three out of 119 water monitoring sites report water quality indexes that meet the general national standard, the bureau said.

A major tributary of the Yangtze River, the Tuojiang River was seriously polluted in February to March 2004, when a chemical factory at the upper reach of the river released tons of waste water, causing the water supply to millions of people to be temporarily cut.

The province has set up 106 monitoring stations that will provide concise data on environmental conditions for the entire province.

(Xinhua News Agency February 25, 2006)