A miner with a donkey makes his way through the low and narrow tunnel leading out of a coal mine in Choa Saidan Shah in Punjab province, April 29, 2014. Workers at this mine in Choa Saidan Shah dig coal with pick axes, break it up and load it onto donkeys to be transported to the surface. Employed by private contractors, a team of four workers can dig about a ton of coal a day, for which they earn around $10 to be split between them. The coalmine is in the heart of Punjab, Pakistan's most populous and richest province, but the labourers mostly come from the poorer neighbouring region of Khyber Pakhtunkhwa. (Photo by Sara Farid/Reuters)

A man salts a downtown sidewalk in Washington, Thursday, March 5, 2015, as snow begins to fall. The U.S. federal government said its offices in the Washington area will be closed Thursday because of a new round of winter weather expected in the region. The Office of Personnel Management said non-emergency personnel in and around Washington were granted excused absences for the day. Emergency employees and telework-ready employees were expected to work. (AP Photo/Andrew Harnik)

Gelada baboons (Theropithecus gelada) play in their enclosure at the Zoo in Zurich, Switzerland, Wednesday, May 15, 2013. (Photo by Steffen Schmidt/Keystone/AP Photo)

A devotee smiles as she offers prayers during the Swasthani Brata Katha festival in Kathmandu, Nepal January 12, 2017. (Photo by Navesh Chitrakar/Reuters)

Pedestrians have a snowball fight in Times Square following a mandatory shutdown of the streets at 11 p.m. on January 26, 2015 in New York City. New York, and much of the Northeast, is bracing for a major winter storm which is expected to bring blizzard conditions and 10 to 30 inches of snow to the area. (Photo by Alex Trautwig/AFP Photo)

A mahout rides on an elephant in the city of Amritsar, India, 08 November 2015. Such elephants are often accompanied by their caretakers who ask for alms from people in the streets. (Photo by Raminder Pal Singh/EPA)

A participant of “Bread Procession of the Saint”, takes part in the ceremony in honor of Domingo de La Calzada Saint (1019-1109) who helped poor people and pilgrimage, in Santo Domingo de La Calzada, northern Spain, Wednesday, May 11, 2016. Every year during spring season, “Las Doncellas” (White Virgins), hold on their head a basket cover with white cloth while they walk past along of this old village in honor of the saint. (Photo by Alvaro Barrientos/AP Photo)

A group of students sit on top of a bus at Kemusu street in Boyolali, Central Java of Indonesia, March 20, 2015 in this picture taken by Antara Foto. (Photo by Yusuf Nugroho/Reuters/Antara Foto)