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)

Elizabeth Svensson (right), 35 and Klaudia Zakrzewska, 27, from London, arrive back in the UK at Heathrow Terminal 2, after being on holiday in Dubai for 15 days, during England's third national lockdown to curb the spread of coronavirus on Friday January 29, 2021. (Photo by Yui Mok/PA Images via Getty Images)

A server carries mugs during a barrel tapping at a beer garden near Theresienwiese where Oktoberfest would have started today as COVID-19 continues in Munich, Germany, September 19, 2020. (Photo by Andreas Gebert/Reuters)

Members of the Texas Dancin' Divas take part in the Juneteenth Parade in Galveston, Texas, U.S., June 19, 2021. The United States marked Juneteenth for the first time as a federal holiday commemorating the end of the legal enslavement of Black Americans. (Photo by Adrees Latif/Reuters)

A Palestinian man sells corn at Gaza Beach during sunset on August 8, 2021. (Photo by Sameh Rahmi/NurPhoto/Rex Features/Shutterstock)

An artist applies henna on the hand or a woman during the Hindu festival of lights, Diwali, in Taipei, Taiwan, Thursday, November 4, 2021. Millions of people across Asia are celebrating the Hindu festival of Diwali, which symbolizes new beginnings and the triumph of good over evil and light over darkness. (Photo by Chiang Ying-ying/AP Photo)

Travellers wait in queue to test for COVID-19 at a train station in Mumbai, India, Tuesday, November 30, 2021. (Photo by Rafiq Maqbool/AP Photo)

A dog plays with a giant soap bubble in downtown Kiev, Ukraine, 06 March 2020. (Photo by Sergey Dolzhenko/EPA/EFE)