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)

A Russian female military cadet marches in front of the Eternal Flame at the WWII memorial complex at Poklonnaya Hill in Moscow on February 17, 2021, during a rehearsal for the upcoming February 23's Defender of the Fatherland Day. (Photo by Alexander Nemenov/AFP Photo)

Russian people walk during heavy rain in Moscow, Russia on 17 September 2020. Over two hours a third of the monthly average rainfall fell in Moscow. (Photo by Yuri Kochetkov/EPA/EFE)

A college girl takes part in the Holi festival celebrations in Bhopal, India, 19 March 2019. Holi is celebrated on the full moon day and marks the beginning of the spring season. Holi will be celebrated as the Hindu spring festival of colors across the country on 21 March. (Photo by Sanjeev Gupta/EPA/EFE)

Entomologist Anna Platoni wears a hat made of tropical flowers made by florist Emma Reynolds with a Blue Morpho butterfly on her cheek to mark the opening of Butterflies in the Glasshouse at RHS Garden Wisley, south of London, on Janurary 15, 2016. (Photo by Luke MacGregor/PA Wire/RHS)

An artist wearing a coronavirus-shaped helmet and a protective suit stands next to a police barricade as he requests people to stay at home during an extended lockdown to slow the spread of the coronavirus disease (COVID-19) in New Delhi, India, April 30, 2020. (Photo by Adnan Abidi/Reuters)

A cadet lies on the grass after collapsing during a promotion ceremony at a police school in Bogota December 7, 2012. (Photo by John Vizcaino/Reuters)

A zoo keeper holds a month old striped Hyena cub called Hachi at the Bali zoo in Giayar, Bali Indonesia on Saturday, February 6, 2021. (Photo by Firdia Lisnawati/AP Photo)