A muslim pilgrim walks through the site where dead bodies are gathered in Mina, Saudi Arabia during the annual hajj pilgrimage on Thursday, September 24, 2015. Hundreds were killed and injured, Saudi authorities said. The crush happened in Mina, a large valley about five kilometers (three miles) from the holy city of Mecca that has been the site of hajj stampedes in years past. (Photo by AP Photo)

Model Yasmine Petty arrives on the Life Ball plane on May 15, 2015 in Vienna, Austria. The Life Ball, an annual charity ball raising funds for HIV & AIDS projects, will take place on May 16, 2015 at the city hall in Vienna. (Photo by Monika Fellner/Getty Images)

These two young siblings appear to cling on to a tree for dear life and even hold hands as they learn the ropes of climbing, on June 25, 2013. (Photo by Tim Fitzharris/Minden/Solent)

A man pours mud water on the head of his girl friend during the Boryeong Mud Festival at Daecheon Beach in Boryeong, South Korea, Friday, July 18, 2014. The annual mud festival features mud wrestling and mud sliding. (Photo by Ahn Young-joon/AP Photo)

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)

(L-R) Recording artists Ally Brooke, Normani Hamilton, Dinah-Jane Hansen, Lauren Jauregui and Camila Cabello of Fifth Harmony attend the 2016 Billboard Music Awards at T-Mobile Arena on May 22, 2016 in Las Vegas, Nevada. (Photo by David Becker/Getty Images)

Artists perform during the Closing Ceremony of the Rio 2016 Olympic Games at the Maracana Stadium in Rio de Janeiro, Brazil, 21 August 2016. (Photo by Sergei Ilnitsky/EPA)

A family pose for a picture as thousands of redheads fill a Dutch city Breda to celebrate International Redhead Day event in Breda, The Netherlands on Sunday, 4 September 2016. Every year natural redheads from more than 80 countries come together at “Roodharigendag” annual weekend long festival to celebrate their ginger genes. The event also holds the world record for the largest number of natural redheads being in one place. (Photo by Akmen/London News Pictures)