A child coughs as migrants and refugees run away after Macedonian police fired tear gas at hundreds of Iraqi and Syrian migrants who tried to break through the Greek border fence in Idomeni, on February 29, 2016. Greek police said more than 6,000 people were massed at the border, in a buildup triggered by Austria and Balkan states capping the numbers of migrants entering their territory. (Photo by Louisa Gouliamaki/AFP Photo)

Maya, 8, and Kishore, 13, pose for a wedding photo inside their new home, the day after the Hindu holy day of Akshaya Tritiya, called Akha Teej in North India. Despite legislation forbidding child marriage in India (Child Marriage Restraint Act-1929) and the much more progressive Prohibition of Child Marriage Act (2006) and many initiatives to prevent child marriage, marrying children off at a very tender age continues to be accepted by large sections of society. (Photo by Stephanie Sinclair/VII Photo Agency)

Indian children work nearby to their parents at a construction project in front of the Jawaharlal Nehru Stadium on January 30, 2010 in New Delhi, India. The children accompany their parents to the work site, where if they are prepared to work, they will receive money for bread an milk and be provided with dinner by the contractor. The sheer scale of the project has drawn an enormous population of migrant workers from all over India.

A displaced Pakistani girl collects recyclable goods from a garbage to earn living for her family in Islamabad, Pakistan, Tuesday, January 19, 2016. (Photo by B.K. Bangash/AP Photo)

A boy looks for scrap metal using an improvised magnetic tool near a construction site in New Delhi, India, March 21, 2016. (Photo by Cathal McNaughton/Reuters)

A girl carries on her head a pile of dried shrubs she gathered for cooking and heating, in Kabul, Afghanistan November 18, 2015. (Photo by Omar Sobhani/Reuters)

Refugees and migrants try to find a place on an already full train headed for Serbia, near the city of Gevgelija, The Former Yugoslav Republic of Macedonia, on February 24, 2016. Refugees and migrants from Iraq and Syria continue to pass through Macedonia on their way to the European Union. (Photo by Georgi Licovski/EPA)

Indigenous Sahrawi girls play on an improvised see-saw at a refugee camp of Boudjdour in Tindouf, southern Algeria March 3, 2016. UN Secretary General Ban Ki-moon is scheduled to visit the Sahrawi refugees in south-west Algeria's Tindouf region. (Photo by Zohra Bensemra/Reuters)