Security personnel patrol around West Lake in Hangzhou, Zhejiang Province, China, August 31, 2016. (Photo by Reuters/Stringer)

A man wearing a mask and dressed in a clown costume rides an electric tricycle while carrying a container in the shape of a rubber duck amid heavy smog in Beijing, China, December 29, 2015. (Photo by Jason Lee/Reuters)

An Afghan teacher, in brown, helps school children run from the site of clashes near the Pakistan consulate in Jalalabad, capital of Nangarhar province, Afghanistan, Wednesday, January 13, 2016. Several members of the Afghan security forces were killed Wednesday after unidentified gunmen attacked the Pakistani consulate in a volatile eastern province, an official said on Wednesday. (Photo by Mohammad Anwar Danishyar/AP Photos)

A woman selling souvenirs walks through Kuta beach in Bali June 5, 2008. Indonesia is expected to report tourist arrivals in December this week. (Photo by Murdani Usman/Reuters)

A migrant labourer brushes his teeth in front of a scrapped helicopter model in Mumbai, India, April 13, 2016. (Photo by Danish Siddiqui/Reuters)

A demonstrator is carried during a rally in support of a identity check draft law and against delinquency, in Santiago, Chile April 30, 2016. (Photo by Carlos Vera/Reuters)

A protester peeks out from behind of a banner as supporters of anti-immigrant activists and nationalists march to protest against the Polish governments decision to accept migrants from Syria and North Africa, in Warsaw, Poland, September12, 2015. EU President Donald Tusk said he would call a special summit on the migration crisis if the bloc's interior ministers do not display “solidarity and unity” at emergency talks on 14 September about the thousands of migrants streaming into Europe. (Photo by Jacek Turczyk/EPA)

The Jet Propulsion Lab team's RoboSimian robot turns on a valve at a simulated disaster-response course during day one of the Defense Advanced Research Projects Agency (DARPA) Robotics Challenge finals in Pomona, California, June 5, 2015. (Photo by David McNew/Reuters)