Growing cities, overuse of fertilizers and factory wastewater have degraded China's water supplies to the extent that half the nation's rivers and lakes are severely polluted. China aims to spend $850 billion to improve filthy water supplies over the next decade, but even such huge outlays may do little to reverse damage caused by decades of pollution and overuse in Beijing's push for rapid economic growth. Photo: Fishermen row a boat in the algae-filled Chaohu Lake in Hefei, Anhui province, June 19, 2009. (Photo by Jianan Yu/Reuters)

Iggy Azalea shares a joke with Andy Lee and Hamish Blake during Bonds 100th birthday celebration event at Cafe Sydney on August 19, 2015 in Sydney, Australia. (Photo by Brendon Thorne/Getty Images)

Clearing skies await a tripod-toting photographer looking for a spot to capture the early-morning light at Portland Head Light, Thursday, January 17, 2013, in Cape Elizabeth, Maine. (Photo by Robert F. Bukaty/AP Photo)

A devotee lights oil lamps at a religious ceremony during the Diwali or Deepavali festival at a Hindu temple in Colombo, Sri Lanka October 18, 2017. Diwali, the Hindu festival of lights, marks the triumph of good over evil, and commemorates the return of Hindu deity Rama to his birthplace Ayodhya after victory against the demon king Ravana. (Photo by Dinuka Liyanawatte/Reuters)

Armed women attend a rally to show support to the Houthi movement in Sanaa, Yemen January 13, 2018. (Photo by Khaled Abdullah/Reuters)

A man carries a woman across a river at Petit Goave where a bridge collapsed during the rains of the Hurricane Matthew, southwest of Port-au-Prince, October 5, 2016. (Photo by Hector Retamal/AFP Photo)

A gun is seen next to the body of a man was killed in a shootout with police in Manila, Philippines early October 21, 2016. According to the police, sachets containing substance believed to be drug shabu (Methamphetamine Hydrochloride) were found in the killed man's pockets. (Photo by Damir Sagolj/Reuters)

Iraqi army soldiers warm themselves next to a fire near the Qayara air base, south of Mosul, Iraq, Tuesday, November 1, 2016. The U.N. human rights office is lauding efforts by the U.S.-led coalition in the battle against the Islamic State group in Mosul. The office in Geneva says coalition flights over Iraq have largely succeeded in preventing IS from bringing in 25,000 more civilians to the city center, where the militant group has been using people as human shields as Iraqi forces advance on Mosul. (Photo by Felipe Dana/AP Photo)