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)

Staff of a boat restaurant on the Taedong River line up at the entrance as they wait to greet customers Sunday, June 18, 2017, in Pyongyang, North Korea. The boat is berthed along the river, which is the fifth longest river on the Korean Peninsula and runs through the country's capital, Pyongyang. (Photo by Wong Maye-E/AP Photo)

A fireman pulls a woman and her dog to shore, by a row of houseboats on the river Seine in Paris France, Wednesday June 1, 2016. The Seine River has overflowed embankments in Paris as floods hit or threaten cities and towns around France. (Photo by Jerome Delay/AP Photo)

A river otter (lontra longicaudis) of 6-weeks-old looks in the mirror during a bath in the Animal Welfare Unit of the Zoo in Cali, Colombia, on October 22, 2019. The baby otter was found abandoned brought to the Cali Zoo for breeding, for its extensive experience in raising these species. According to the International Union for Conservation of Nature the river otter (lontra longicaudis) are in danger of extinction, because of mining, agriculture, pollution of rivers and housing construction in their habitat. (Photo by Luis Robayo/AFP Photo)

A monkey drinks water from a tap on a hot afternoon in Jammu, the winter capital Kashmir, India, 17 May 2016. Temperatures of around 42 degrees Celsius were forecast in the region. According to the news reports the Indian government decided to divert water by its river interlinking plans from rivers like Brahmaputra and the Ganges towards those rivers facing the drought likesituation . Many Indian states have been affected by drought and have been hit hard by water scarcity. (Photo by Jaipal Singh/EPA)

Tim Anderson final balanced rock stack in the Llano River. Tim Anderson, rock balancing “pro” from Pennsylvania, carefully worked to balance his stack on a dry spot in the Llano river Saturday March 12, 2016. He was an honored guest of the festival and enjoyed visiting Texas so he came for another year. The river was higher this year because of the rains so the balancers could not get to the better rock that were available last year. (Photo by Nell Carroll/American-Statesman)

A boat commutes across the Mekong river in Phnom Penh on August 8, 2014. The Mekong is the world's twelth longest river running from the Tibetan Plateau through China's Yunnan province, Myanmar, Laos, Thailand, Cambodia and Vietnam. (Photo by Tang Chhin Sothy/AFP Photo)