Among the 22 people who signed the petition are seven, including its drafter, Ling Cangzhou, from Charter 08's first group of signatories.

ECONOMIST: Dissent in China

But planners failed to consider the limits of the city's water supply and Cangzhou now faces one of the most severe water shortages in northern China.

ECONOMIST: China

The city of Cangzhou, in Hebei province, decided a few years ago that its path to prosperity lay in making itself a centre of the chemical industry.

ECONOMIST: China