This file photo shows a polluted river, once used for swimming by local youths, in Liukuaizhuang Village in Tianjin, southeast of Beijing, on March 16, 2006. China's environment ministry has ... more 

This file photo shows a polluted river, once used for swimming by local youths, in Liukuaizhuang Village in Tianjin, southeast of Beijing, on March 16, 2006. China's environment ministry has acknowledged the existence of 'cancer villages', several years after widespread speculation first began that polluted areas were seeing a higher incidence of the disease less