A Syrian migrant family enters Hungary at the border with Serbia near Roszke, Hungary August 28, 2015. As Europe struggles with its worst migrant crisis since World War II, Hungary has become, like Italy and Greece, a “frontline” state. So far this year, police say around 141,500 migrants have been intercepted crossing into Hungary, mostly from neighbouring Serbia. (Photo by Bernadett Szabo/Reuters)

A child uses an umbrella to avoid rain falling on a fire at the northern Greek border point of Idomeni, Greece, Monday, April 25, 2016. Many thousands of migrants remain at the Greek border with Macedonia, hoping that the border crossing will reopen, allowing them to move north into central Europe. (Photo by Gregorio Borgia/AP Photo)

Girls hold hands as they help each other wade through a flooded street after the passing of Hurricane Matthew in Les Cayes, Haiti, Thursday, October 6, 2016. Two days after the storm rampaged across the country's remote southwestern peninsula, authorities and aid workers still lack a clear picture of what they fear is the country's biggest disaster in years. (Photo by Dieu Nalio Chery/AP Photo)

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)

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)

A group of people wearing Santa Claus hats and swimming suits participate in the 13th charity Great Santa Claus Run in downtown Budapest, Hungary, Sunday, December 11, 2016. (Photo by Balazs Mohai/MTI via AP Photo)

Residents cross a swelling dam, due to rising waters brought about by Typhoon Koppu, in Las Pinas city, metro Manila October 19, 2015. Powerful typhoon Koppu ploughed into the northeastern Philippines before dawn on Sunday destroying homes and displacing 10,000 people and whipping up coastal surges four meters (12 feet) high, disaster agency officials said. (Photo by Ezra Acayan/Reuters)

A young man, who says he is part of a local criminal gang, poses for a picture holding a gun in the neighbourhood of Korogcho in Nairobi, Kenya, March 19, 2015. Around 2 million people live in the shantytowns packed in around Kenya's capital. Crime is high amid chronic unemployment levels, while basic services and sanitation are scarce. Residents try to make the best of things, eking out a living and picking up work where they can. (Photo by Siegfried Modola/Reuters)