A boy throws a banana after collecting it from the polluted waters of river Sabarmati, in Ahmedabad July 18, 2013. (Photo by Amit Dave/Reuters)

A boy searches for coins thrown by devotees as religious offerings in a polluted water channel near a temple in Kolkata June 5, 2014. (Photo by Rupak De Chowdhuri/Reuters)

A man swims in the polluted waters of river Yamuna on a hot day in New Delhi May 29, 2013. (Photo by Mansi Thapliyal/Reuters)

A man pours water on the polluted banks of river Ganges beside the idols of Hindu god and goddess that were immersed during the Durga Puja festival in Kolkata October 20, 2010. (Photo by Reinhard Krause/Reuters)

Boys collect coconuts thrown in as offerings by worshippers in the waters of the Sabarmati river after the immersion of idols of Lord Ganesh, the deity of prosperity, in Ahmedabad September 12, 2011. (Photo by Amit Dave/Reuters)

Children stand in a boat at the banks of the polluted Yamuna River during a dust haze as they wait to give a ride to worshippers in New Delhi during World Environment Day June 5, 2010. (Photo by Reinhard Krause/Reuters)

Workers carry algae as they clean the polluted waters of river Sabarmati on World Environment Day in Ahmedabad June 5, 2013. (Photo by Amit Dave/Reuters)

A boy swims in the polluted waters of the river Sabarmati to dive for offerings thrown in by worshippers in Ahmedabad August 20, 2010. (Photo by Amit Dave/Reuters)

Rag pickers search for recyclable materials from the polluted banks of the Yamuna river in Allahabad December 14, 2009. (Photo by Jitendra Prakash/Reuters)

Residents of a slum sit on water pipes going over the contaminated Mithi River in Mumbai December 16, 2009. (Photo by Arko Datta/Reuters)

A devotee takes a holy dip in the polluted Sangam, confluence of three rivers, the Ganga, the Yamuna and mythical Saraswati, in Allahabad November 10, 2008. (Photo by Jitendra Prakash/Reuters)

A government worker pours adulterated milk into the Kuvam river in Chennai July 24, 2008. (Photo by Reuters/Babu)

A man casts a fishing net into the polluted waters of river Yamuna in Agra March 7, 2007, with the historic Taj Mahal monument in the background. (Photo by Adeel Halim/Reuters)