An armed youth loyal to the Houthi movement takes part in a protest against the Saudi-backed exiled government deciding to cut off the Yemeni central bank from the outside world, in the capital Sanaa, Yemen August 25, 2016. (Photo by Mohamed al-Sayaghi/Reuters)

An Afghan girl carries water on her back as she climbs a hill in Kabul, Afghanistan February 20, 2017. A growing population is straining water supplies in Afghanistan's capital, forcing those who can afford it to dig unregulated wells ever deeper to tap a falling water table. Finding water in arid Afghanistan is virtually always a challenge, but a drop in the groundwater level in Kabul caused by overuse and drought is making it even more difficult for residents, especially the poor. (Photo by Omar Sobhani/Reuters)

A girl plays in the Eshash el-Sudan slum in the Dokki neighbourhood of Giza, south of Cairo, Egypt September 2, 2015. Residents of the slum clashed with police in late August, when about 50 ramshackle huts were destroyed and at least 20 people were injured by teargas, local media reported, as authorities attempt to clear the area and rehouse residents. The slum dwellers, some of whom have called Eshash el-Sudan home for 50 years, say there are not enough apartments built nearby to house them. The residents of the slum eke out a living by disposing of rubbish or baking bread. Schooling is too expensive for most of their children, who play with salvaged rubbish amid shacks made out of discarded wood and leather. (Photo by Amr Abdallah Dalsh/Reuters)

Participants from Newar community in traditional attire, takes part in the parade to celebrate Newari New Year that falls during the Tihar festival, also called Diwali, in Kathmandu, Nepal November 12, 2015. The Newar community observes the start of their Newari New Year 1136, in accordance with their lunar calendar, by worshipping their spiritual selves in a ritual known as "mahapuja". (Photo by Navesh Chitrakar/Reuters)

Children sit on a bed in a flooded house following heavy rain in a village in Yemen's Red Sea province of Houdieda April 15, 2016. (Photo by Abduljabbar Zeyad/Reuters)

Soldiers with the Afghan National Army (ANA) at an outpost in the Momand Valley on July 16, 2017 in Achin District, Afghanistan. The building was previously used as of a jail by the Islamic State of Iraq and Syria – Khorasan (ISIS-K) and was taken by Afghan Commandos nine days prior. Operations are currently underway to remove ISIS fighters from Nangarhar Province in Eastern Afghanistan. (Photo by Andrew Renneisen/Getty Images)

People stand by a damaged car at a train station at a makeshift camp for migrants and refugees at the Greek-Macedonian border near the village of Idomeni, Greece, May 10, 2016. (Photo by Marko Djurica/Reuters)

A Hindu holy man or Sadhu walks back to his ashram after taking a dip at Sangam, confluence of Ganges river, Yamuna river and mythical Saraswati river in Allahabad, India, Thursday, August 4, 2016. (Photo by Rajesh Kumar Singh/AP Photo)