Couples take part in a competition during a mass wedding of 64 doctoral student couples at Harbin Institute of Technology, a university in Harbin, Heilongjiang province, China, June 4, 2017. (Photo by Reuters/Stringer)

A commuter exits a closed off station after a subway train derailment, Tuesday, June 27, 2017, in the Harlem neighborhood of New York. A subway train derailed near a station in Harlem on Tuesday, frightening passengers and resulting in a power outage as people were evacuated from trains along the subway line. The Fire Department of New York said a handful of people were treated for minor injuries at around 10 a.m. It said there was smoke but no fire. Delays were reported throughout the subway system. (Photo by Mary Altaffer/AP Photo)

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)

Migrants prepare their food outside shelters in a muddy field called the Grande-Synthe jungle, near Dunkirk, northern France, January 12, 2016. The Grande-Synthe jungle is a camp of tents and makeshift shelters where migrants and asylum seekers from Irak, Kurdistan and Syria gather. (Photo by Benoit Tessier/Reuters)

A selection of hand-made leis, traditional Hawaiian necklaces made of flowers and worn mostly on special occasions, fill a cooler at Lin's Lei Shop in the Chinatown district of Honolulu, Hawaii December 22, 2015. Hawaii, whose economy depends heavily on tourism, sees a brief lull in visitors each year in January and February. But in addition to the usual tourist destinations, the state shows a unique overlay of mainland U.S. culture atop tropical beauty year-round. (Photo by Jonathan Ernst/Reuters)

A woman scales fish by the side of a lake as she prepares for the upcoming Chinese Lunar New Year in Suqian, Jiangsu province, China, January 27, 2016. (Photo by Reuters/China Daily)

Indian dancers perform a fire breathing act during a procession to mark the 661st anniversary of the birth of Hindu guru Bawa Lal Dayal Maharaj in Amritsar on February 9, 2016. Bawa Lal Dayal Maharaj, a popular leader of his time, is especially revered by devotees of a temple in the town of Dhyanpur, some 45 kms north of Amritsar. (Photo by Narinder Nanu/AFP Photo)

Paramilitary policemen carry tyres as they take part in a training session in Zhangye, Gansu Province, China, March 1, 2016. (Photo by Reuters/Stringer)