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)

Danila Shmelev, an artist from Moscow, Russia, works on a 3-D picture in Dubai, United Arab Emirates, Monday, February 27, 2017. Artists who focus on 3-D pictures have gathered in Dubai for the Dubai Canvas 3-D Art Festival, which runs from March 1 through March 7. (Photo by Jon Gambrell/AP Photo)

Rapper Pitbull performs onstage during Nickelodeon's celebration of the new Burbank facility on January 11, 2017 in Los Angeles, California. (Photo by Charley Gallay/Getty Images for Nickelodeon)

A visitor poses for a photo with a Crayon Shin-chan model during an exhibition at Joy City in Beijing May 5, 2015. The exhibition, which showcased fifty models of the Japanese cartoon character in different poses and expressions, will run from April 18 to June 22. (Photo by Jason Lee/Reuters)

A man presents a self-made robot that local media reported is able to carry a person, in Heihe, Heilongjiang province, China, April 5, 2017. (Photo by Reuters/China Daily)

Members of the Albert Battery perform a gun salute during the Anzac Day dawn service held by the Currumbin RSL on the Gold Coast in Currumbin, Australia, 25 April 2016. The Anzac day marks the landing of the Australian and New Zealand Army Corps (Anzac) troops at Gallipoli in what is today Turkey during WWI. World War One, also called the Great War, according to official statistics cost more than 37 million military and civilian casualties between 1914 and 1918. (Photo by Glenn Hunt/EPA)

A traffic police woman whistles at a pedestrian, Monday, July 27, 2015, in Pyongyang, North Korea where its citizens are having a one-day national holiday to celebrate the country's 62nd anniversary of the armistice that ended the Korean War. (Photo by Wong Maye-E/AP Photo)

A Hindu devotee is helped by other people as she walks on burning coals during a religious procession Vel Festival of the Hindu goddess Maha Mariamman (Sheetla Mata), in New Delhi, India, 06 April 2017. People get their bodies pierced with different kinds of metal needles and rods and participate in a religious procession as thanks giving gesture to the goddess in return of their fulfilled wishes during the annual procession. (Photo by Rajat Gupta/EPA)