A research group in China has found that industrial pollution and urban sewage has made one-third of the water in the Yellow River unusable. From The Guardian:
The survey, based on data taken last year, covered more than 8,384 miles of the river, one of the longest waterways in the world, and its tributaries.
The Yellow River Conservancy Committee, affiliated to the ministry of water resources, said 33.8% of the river system’s water sampled in 2007 registered worse than level five. That means it is unfit for drinking, aquaculture, industrial use and even agriculture, according to criteria used by the UN Environment Programme.
Only 16% of the river samples reached level one or two, the standard considered safe for domestic use.