A man selling bags of water is seen at a taxi parking bay lined with campaign posters in the district of Lingwala in Kinshasa on December 18, 2018. Democratic Republic of Congo goes to the polls on December 23, 2018 in elections which could see the country emerge from 17 years of conflict-ridden rule under controversial President Joseph Kabila. (Photo by John Wessels/AFP Photo)

A woman wears a face mask in the part of the city near neighbourhoods known for burning coal for heating in Ulaanbaatar, Mongolia January 26, 2017. Not many people in Ulaanbaatar wear masks to protect themselves against pollution. (Photo by B. Rentsendorj/Reuters)

Models of the SibPlus Models agency and participants of the Miss Doughnut beauty competition take part in a rehearsal in Krasnoyarsk, Siberia, Russia, March 4, 2017. (Photo by Ilya Naymushin/Reuters)

In this May 2016 photo released by The Ocean Agency/XL Catlin Seaview Survey, a boat sails near a coral reef that has been bleached white by heat stress in the Maldives. oral reefs, unique underwater ecosystems that sustain a quarter of the world's marine species and half a billion people, are dying on an unprecedented scale. Scientists are racing to prevent a complete wipeout within decades. (Photo by The Ocean Agency/XL Catlin Seaview Survey via AP Photo)

An elderly man uses a fan to shade himself from the sun as he walks in a public park in Beijing, Tuesday, June 7, 2016. Thursday marks the Duanwu Festival, a public holiday in China celebrated with outdoor activities including dragon boat races. (Photo by Mark Schiefelbein/AP Photo)

Members of the media film as a ranger performs a post mortem on the carcass of a rhino after it was killed for its horn by poachers at the Kruger national park in Mpumalanga province August 27, 2014. Rhino poachers in South Africa now risk giving themselves away when they shoot thanks to a high-tech, gunfire-detection system being piloted in the country's flagship Kruger National Park. The stakes are high, for rhinos are being slain in escalating numbers for their prized horns, alarming both conservationists and the government since wildlife in South Africa is an important tourist draw. (Photo by Siphiwe Sibeko/Reuters)

In this November 20, 2017 photo, Indian kushti wrestlers fight in the ring, during their daily training at an akhada, a kind of wrestling hostel at Sabzi Mandi, in New Delhi, India. Like many traditions in rapidly modernizing India, kushti wrestling faces the threat of being left behind. But for many poor families, the ancient sport provides a glimmer of hope. (Photo by Dar Yasin/AP Photo)

Young Turkana tribeswomen sing in a village near Baragoy, Kenya August 6, 2017. Kenyans are due to go to the polls on Aug. 8. to vote in presidential elections after a tightly-fought race between President Uhuru Kenyatta and main opposition leader Raila Odinga. (Photo by Goran Tomasevic/Reuters)