Kashmiri children play with snow on a wooden foot bridge in the interiors of Dal Lake in Srinagar on January 16, 2017. A cold wave has further tightened its grip in Jammu and Kashmir, with most places in the state recording sub-zero temperatures. (Photo by Tauseef Mustafa/AFP Photo)

Young children at a Bristol, Great Britain health centre unsure of the benefits of sun-lamps and the special glasses that must be worn, July 1948. The health centre was part of the newly introduced free National Health Service. (Photo by Popperfoto/Getty Images)

A young reveller participates in the annual Trinidad and Tobago Red Cross Society's Children's Carnival Competition at the Queen's Park Savannah in Port-Of-Spain, Trinidad and Tobago February 18, 2017. (Photo by Andrea De Silva/Reuters)

Afghan children wait as their mothers receive treatment at a USAID-funded health center on September 7, 2011 in Farza, Afghanistan. Almost 10 years after the 9/11 attacks and the U.S. invasion of Afghanistan, the U.S. government funds some of 500 Afghan health facilities nationwide, most run by non-governmental organizations contracted by the Afghan Ministry of Public Health. (Photo by John Moore/Getty Images)

Malena, 7, looks at Belgian clown Lili Bellule at the pediatric department of the Hopital Erasme at the Universite Libre de Bruxelles (ULB), in Brussels January 27, 2015. The hospital offers performances by musicians and clowns as a form of therapy to help children cope with dealing with the stress and fear caused by hospitalization. (Photo by Yves Herman/Reuters)

A member of “Laughter Doctors of Ciudad Juarez” performs at a children's hospital in Ciudad Juarez March 11, 2015. Through clown performances, music and interactive activities, the group of doctors visit different hospitals throughout the border city, using laughter to help aid the recovery of young and elderly patients suffering from serious illness or injury, as well as provide hope for the hospitalized patients and their families, local media reported. (Photo by Jose Luis Gonzalez/Reuters)

Izzy Paskowitz helps Nixee Grace Chanowsky, 4, catch a wave Monday, August 18, 2014 at Wrightsville Beach, N.C. during the Annual Surfers Healing event for children with autism. Hundreds of people made their way to the beach to watch and cheer on the camp that was founded by Israel and Danielle Paskowitz. (Photo by Mike Spencer/AP Photo/The Star-News)

A Syrian boy receives treatment at a hospital in the regime-held part of Aleppo on October 13, 2016. Syrian state television said four children were killed by rebel rocket fire on a school in a western regime-held neighbourhood. (Photo by George Ourfalian/AFP Photo)