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)

Saint Nicholas poses with students during a traditional parade in central Brussels, Belgium December 3, 2016. (Photo by Yves Herman/Reuters)

Women take a selfie next to a police officer as they take part in New Year's Eve celebrations in the Bund, in Shanghai, China December 31, 2016. (Photo by Aly Song/Reuters)

An “asparagus eating contest” made of asparagus and carved pumpkins is on display on the sidelines of the Giant Vegetable Competition in Klaistow, northeastern Germany, on September 20, 2015. The vegetable giants compete in seven categories. (Photo by Bernd Settnik/AFP Photo)

People walk through crop circles in a cornfield near Raisting, Germany, on July 28, 2014. According to media reports, a balloonist had discovered the circle some days ago. Since then, hundreds of people came to the field to watch it, however it is unclear who did create the pattern. (Photo by Karl-Josef Hildenbrand/DPA)

A woman prays at the edge of a river during a protest against the building of a pipeline near the Standing Rock Indian Reservation near Cannonball, North Dakota, U.S. November 2, 2016. (Photo by Stephanie Keith/Reuters)

A girl pulls her sister in a discarded basket in the Rashidabad neighborhood of Peshawar, Pakistan October 18, 2015. (Photo by Khuram Parvez/Reuters)

Two stags fight in a wildlife park in Aurach near Kitzbuehel, in the Austrian province of Tyrol. (Photo by Kerstin Joensson/Associated Press)