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)

Seven month old Christine Joy shares her pram with two 5 week old Gunsure Golden Cherry's cocker spaniel pups from Gunsure Kennels in Ashford, Middlesex. 22nd May 1953. (Photo by Fred Morley/Fox Photos)

A polar bear fast asleep at London Zoo. (Photo by Fox Photos/Getty Images). 1961

A car drives past burning trees as a wildfire rages in the northern city of Haifa, Israel November 24, 2016. Hundreds of Israelis fled their homes on the outskirts of the country's third city Haifa with others trapped inside as firefighters struggled to control raging bushfires, officials said. (Photo by Gil Eliyahu/Reuters)

A girl carries a bag of recyclable items she collected from a landfill on the outskirts of Sanaa, Yemen November 16, 2016. (Photo by Mohamed al-Sayaghi/Reuters)

Festivalgoers watch two actors of the Wasteland Warriors movement fight in a cage at the world's largest heavy metal festival, the Wacken Open Air 2019, in Wacken, Germany on August 3, 2019. Wacken is a village in northern Germany with a population of 1,800 that has hosted the annual festival, which attracts heavy metal fans from around the world, since 1990. (Photo by Wolfgang Rattay/Reuters)

Sad woman standing near car with scratch on parking and talking by the phone. (Photo by Vera Petrunina/Getty Images)

A mahout bathes his elephant in the river Sabarmati on a hot summer day in Ahmedabad, India May 21, 2017. (Photo by Amit Dave/Reuters)