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 handout photograph provided by Brian Kubicki of Costa Rican Amphibian Research Center on 26 April 2016 shows a “Crystal frog”, Hyalinobatrachium dianae (H. diane). This frog was discovered by US biologist Brian Kubicki and Costa Ricans Stanley Salazar and Robert Puschendorf in a rainy forest of Costa Rican caribbean after 40 years without notice of any new example of this kind. (Photo by Brian Kubicki/EPA/Costa Rican Amphibian Research Center)

In this June 29, 2015 photo, hairdresser Loavia Bienaime, 30, sits on her bed as she prepares to begin her day in the room her family occupies in an government office building that was damaged in the 2010 earthquake in Port-au-Prince, Haiti. Bienaime's husband, Jimmy Bellefleur, used his skill as an electrician to connect the abandoned building to the power grid, and has repaired broken televisions, fans, and a blender for the family to use. (Photo by Rebecca Blackwell/AP Photo)

Clearing skies await a tripod-toting photographer looking for a spot to capture the early-morning light at Portland Head Light, Thursday, January 17, 2013, in Cape Elizabeth, Maine. (Photo by Robert F. Bukaty/AP Photo)

A Black Pete interacts with children during the arrival of Sinterklaas, or Saint Nicholas, in Maassluis, Netherlands, Saturday, November 12, 2016. Sinterklaas and his helper Black Pete are at the center of a long-time controversy because Pete is often played by white people in blackface makeup. (Photo by Peter Dejong/AP Photo)

A Hindu pilgrim feeds biscuits to an ox to seek blessing before heading for an annual trip to Sagar Island for the one-day festival of “Makar Sankranti”, in Kolkata, India January 10, 2017. (Photo by Rupak De Chowdhuri/Reuters)

Green Bay Packers' Johnathan Calvin rides a bike to NFL football training camp on July 27, 2017, in Green Bay, Wis. (Photo by Morry Gash/AP Photo)

2016 Rio Olympics, Athletics, Final, Women's 200m Final, Olympic Stadium, Rio de Janeiro, Brazil on August 17, 2016. Photographers take pictures of Elaine Thompson (JAM) of Jamaica after she won the gold. (Photo by Gonzalo Fuentes/Reuters)