An applicant try-out during a stewardess recruiting interview for China Southern Airlines on October 12, 2006 in Beijing, China. Over 160 candidates have competed at the Beijing Region selection for a total of 15 berths in the next stage of recruitment. The China Southern Airlines launched a nationwide campaign to single out qualified stewardesses, the first of its kind to recruit stewardesses through TV shows. (Photo by China Photos/Getty Images)

A mahout leads an elephant calf to the river Tunga for bathing at the Sakrebailu Elephant Camp in Sakrebailu in the southern state of Karnataka, India, November 12, 2016. (Photo by Abhishek N. Chinnappa/Reuters)

Men help a woman affected by tear gas used by National Police officers to disperse a demonstration of supporters of Fanmi Lavalas political party in the streets of Port-au-Prince, Haiti, November 22, 2016. (Photo by Andres Martinez Casares/Reuters)

A street actor dressed as a devil frightens children in downtown Prague in Prague, Czech Republic, Monday, December 5, 2016. On the eve of St. Nicholas, Czechs traditionally celebrate by dressing up as Devils, Angels and St. Nicholas, and visiting children in their homes handing out small presents, coal, potatoes or other gifts. (Photo by Petr David Josek/AP Photo)

An airplane is silhouetted at sunrise, seen from the suburb of Saint-Cloud, near Paris, France, 08 December 2016. Paris is undergoing a third day pollution spike, prompting the city to limit vehicle circulation. (Photo by Ian Langsdon/EPA)

Members of Hashid Shaabi or Popular Mobilization Forces (PMF) fire towards Islamic State militant positions in west of Mosul, Iraq, December 28, 2016. (Photo by Reuters/Stringer)

Anti-pollution protesters wearing traditional costumes and contemporary gas masks ride bicycles in the Qingming Grand river park in Kaifeng, Henan Province, China on January 1, 2017. The Beijing Municipal Environmental Protection Bureau extended an “orange alert” for heavy air pollution for three more days. (Photo by SIPA Asia/Rex Features/Shutterstock)

A roadside ice-cream vendor waits for customers at a market in New Delhi, India, April 7, 2016. The Indian economy is characterized by the existence of a vast majority of informal or unorganized labor employment. (Photo by Altaf Qadri/AP Photo)