Thanks to an all-out cleanup campaign, the coal tar sludge spilled from an overturned truck has flowed only 1.5 km down the Dasha River in north China in 42 hours, officials said yesterday.

The sludge was 52 km away from a downstream reservoir in Fuping County, Hebei Province at 5?AM Sunday, said officials with the local environmental protection bureau.

An overloaded truck carrying 80 tons -- the initial figure given by officials was 60 tons -- of coal tar overturned in Fanzhi County, Shanxi Province at 5 PM on June 12, and spilled part of its load into the Dasha River, which originates in Shanxi and flows 80 km to Fuping.

The polluted part of the river has turned brown and smells strongly even from tens of meters away.

Cleanup workers have built 51 temporary dams along the river to halt the spill's movement in an effort to minimize the threat to the Wangkuai Reservoir, which is the drinking water source for Hebei's 10 million residents and also a standby for the Beijing 2008 Olympic Games.

Fuping's cleanup workers succeeded in building a major dam 370 meters long,?five meters high and 20 meters wide on Saturday morning. The structure can hold 200,000 cubic meters of water.

Fifty-three pumps have removed 1,700 tons of polluted water since the dam was built.

The local governments of Fanzhi and Fuping are making every effort to prevent the pollution from entering the reservoir. Over 100 dredging machines and 100,000 people in Hebei have been mobilized to help build dams and conduits to slow down the sludge flow.

Activated carbon, cotton quilts and sponge material have been placed in the river to absorb the pollutant.

(Xinhua News Agency June 19, 2006)