Ethnic Cham Muslim people pass the time near their boats on banks of Mekong river in Phnom Penh July 29, 2013. About 100 ethnic Cham families, made up of nomads and fishermen without houses or land who arrived at the Cambodian capital in search of better lives, live on their small boats on a peninsula where the Mekong and Tonle Sap rivers meet, just opposite the city's centre. The community has been forced to move several times from their locations in Phnom Penh as the land becomes more valuable. They fear that their current home, just behind a new luxurious hotel under construction at the Chroy Changva district is only temporary and that they would have to move again soon. (Photo by Damir Sagolj/Reuters)

Residents with their empty containers crowd around a municipal tanker to fetch water in New Delhi, India, February 22, 2016. The Indian army has taken control of a canal that supplies three-fifths of Delhi's water, the state's chief minister said on Monday, raising hope that a water crisis in the metropolis of more than 20 million people can be averted. (Photo by Anindito Mukherjee/Reuters)

Six month- old baby elephant “Clear Sky” is kept afloat with the help of a harness during a hydrotherapy session at a local veterinary clinic in Chonburi Province on January 5, 2017. After losing part of her left foot in a snare in Thailand, baby elephant 'Clear Sky' is now learning to walk again – in water. (Photo by Roberto Schmidt/AFP Photo)

Kangba women carry barrels to fetch water at a village on April 10, 2005 in Zuogong County of Tibet, China. Kangba people began to fetch water with the traditional barrels hundreds of years ago. Kangba people are one of the Tibetan tribes living in Kangba Region, a juncture area of Sichuan and Yunnan Provinces and the Tibet Autonomous Region. Kangba people are famous for their beauty, toughness and straightforwardness. (Photo by China Photos/Getty Images)

A herder stops for reindeers to have a rest while riding along the tundra area in Nenets Autonomous District, Russia, November 27, 2016. In Russia's remote Arctic regions reindeer herding has been a way of life for centuries. Each winter herders in Russia's sparsely populated Nenets Autonomous District corral their reindeers into open-air pens before selecting weak animals to be culled... (Photo by Sergei Karpukhin/Reuters)

Children of local herders gather at a reindeer camping ground, some 200 km (124 miles) northeast of Naryan-Mar, the administrative centre of Nenets Autonomous Area, far northern Russia, August 2, 2015. People, including local herders and members of their families, gathered at the site to mark Reindeer Day, a professional holiday of reindeer breeding workers, which is celebrated annually on August 2 in the region. (Photo by Sergei Karpukhin/Reuters)

Combine harvesters work on a wheat field of the Solgonskoye farming company near the village of Talniki, southwest from Siberian city of Krasnoyarsk, Russia, August 27, 2015. Russia, one of the world's top wheat exporters, will harvest its third-largest grain crop in post-Soviet history this year, leading Russian consultancy SovEcon said on August 27 after upgrading its forecast. (Photo by Ilya Naymushin/Reuters)

Fifth-grade students of the General Yermolov Cadet School get prepared before their first military tactical exercise on the ground, which includes radiation resistance classes, forest survival studies and other activities, in Stavropol, Russia, September 10, 2016. Picture taken September 10, 2016. (Photo by Eduard Korniyenko/Reuters)