Hindon, a tributary of the Yamuna, is so polluted a river that villages on its banks in Bagpat district, Uttar Pradesh, have taken to calling its water zeher. Poison. The zeher seeps into their groundwater, and through handpumps makes its way into their bodies and those of their cattle. It is now the subject matter of a case in the National Green Tribunal, which has thrice ordered clean water to be supplied to these villages - the last on 19 July.