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 Chinese girl peeps at Santa at a shopping center on Christmas Eve December 24, 2011 in Beijing, China. Though Christmas is not officially celebrated in China, the holiday is becoming increasingly popular as Chinese adopt more Western ideas and festivals. (Photo by Feng Li/Getty Images)

Chinese hostesses, who serve the delegates of the Chinese People's Political Consultative Conference and National People's Congress, have souvenir photos taken in front of the Great Hall of the People during sessions of the CPPCC and NPC held in Beijing, China Tuesday, March 4, 2014. (Photo by Andy Wong/AP Photo)

Models promote a condom brand at the first Shenzhen s*x Culture Festival on September 21, 2007 in Shenzhen of Guangdong Province, China. The festival aims to increase awareness about reproductive health and popularise s*x education. (Photo by China Photos/Getty Images)

Rescuers work at the accident scene on a bridge on July 24, 2011 in Wenzhou, Zhejiang Province of China. The train from Hangzhou to the city of Wenzhou derailed on a bridge that is 10 m above the field in Shuangyu Town of Wenzhou city at 8:34 p.m on Saturday. The first four coaches and the 15th and 16th coaches of the train went off the line killed 32 and injured 191 people. (Photo by ChinaFotoPress/Getty Images)

A staff member of Yutian County poses for a video on marigold industry at an agricultural industrial park in Yutian County, northwest China's Xinjiang Uygur Autonomous Region, September 20, 2020. As one of the five counties in Hotan Prefecture that have not been lifted out of poverty, Yutian County is accelerating its steps to shake off poverty by planting marigold. (Photo by Chine Nouvelle/SIPA Press/Rex Features/Shutterstock)

A woman poses for a photo in the tourist area surrounding Houhai Lake during Chinese National Day holidays in Beijing, China, October 2, 2020. China is celebrating its national day marking the 71st anniversary of the People's Republic of China and the Mid-autumn Festival for a week beginning on October 1st. (Photo by Thomas Peter/Reuters)

A migrant worker wearing face masks to help curb the spread of the coronavirus walks up to a pedestrian bridge in Beijing, Sunday, December 6, 2020. Provincial governments across China are placing orders for experimental, domestically made coronavirus vaccines, though health officials have yet to say how well they work or how they may reach the country's 1.4 billion people. (Photo by Andy Wong/AP Photo)