A woman wearing a mask walk in a street in a Yonghegong Lama temple compound seen shrouded in smog in Beijing, China, 30 November 2015. Beijing issued an orange alert for heavy smog 30 November, the highest level this year. Authorities in the Chinese capital warned of 'severe pollution' and advised the capital's 20 million inhabitants to stay indoors. (Photo by How Hwee Young/EPA)

Ruslan Arslanbayev of Russia works on his creation during the Sand Sculpture Festival “Sand Fantasy” in Almaty, Kazakhstan, April 15, 2016. (Photo by Shamil Zhumatov/Reuters)

Waves triggered by Typhoon Hato are seen in Hong Kong, China on August 23, 2017. A powerful typhoon barreled into Hong Kong on Wednesday, forcing offices and schools to close and leaving flooded streets, shattered windows and hundreds of canceled flights in its wake. Typhoon Hato came within 60 kilometers (37 miles) of Hong Kong, close enough to be considered a direct hit under Hong Kong's storm warning system. It was headed toward the western side of mainland China's Pearl River Delta. (Photo by Tyrone Siu/Reuters)

A group of women laugh at artwork referencing U.S. Republican presidential candidate Donald Trump made by the artist Hanksy and being sold at a temporary store in New York, U.S., June 4, 2016. (Photo by Lucas Jackson/Reuters)

Samba dancers perform during the annual Asakusa Samba Carnival in Tokyo, Japan August 27, 2016. Asakusa is a district in Taitō, Tokyo. The neighborhood is famous for its annual Brazilian style carnival. There is a significant Brazilian presence in the local community and the Association of Samba Schools of Asakusa is based there. (Photo by Kim Kyung-Hoon/Reuters)

Children stand in a boat at the banks of the polluted Yamuna River during a dust haze as they wait to give a ride to worshippers in New Delhi during World Environment Day June 5, 2010. (Photo by Reinhard Krause/Reuters)

Sami people from the Vilhelmina Norra Sameby, gather their reindeers herd in a corral for selection and calf labelling on October 27, 2016 near the village of Dikanaess, about 800 kilometers north-west of the capital Sweden. Sweden's Sami reindeer herders have more than hungry predators to worry about in the cold night, as the indigenous minority moves its flock to the winter pasture in the Nordic tundra. (Photo by Jonathan Nackstrand/AFP Photo)

A woman dressed in a costume poses for a photograph at Tokyo Comic Con at Makuhari Messe in Chiba, Japan December 2, 2016. (Photo by Issei Kato/Reuters)