Pedestrians wear masks as smoke and haze from bushfires in New South Wales blankets the CBD in Sydney, Australia, 10 December 2019. The New South Wales environment department says visibility across east and southwest Sydney was at a “hazardous” level on Tuesday morning, while air quality was poor in southwest Sydney and hazardous in northwest Sydney. (Photo by Steven Saphore/EPA/EFE)

A motorway bridge crosses the icy Hunhe River in Shenyang, China on December 12, 2019. (Photo by Costfoto/Barcroft Media)

British Prime Minister Boris Johnson visits the Pavegen stand, a company that converts footsteps into energy, at the Innovation Zone during the UK-Africa Investment Summit in London, Britain on January 20, 2020. (Photo by Leon Neal/Pool via Reuters)

A tourist pauses for photos with her mask on at Sensoji Temple Thursday, January 30, 2020, in Tokyo. The country began evacuating Japanese citizens on Wednesday from the Chinese city Wuhan hardest-hit by the virus. (Photo by Jae C. Hong/AP Photo)

A man wearing a traditional Russian costume holds a goose after a traditional goose fight during celebrations of Maslenitsa, also known as Pancake Week, which is a pagan holiday marking the end of winter, in Suzdal, Russia on February 29, 2020. (Photo by Maxim Shemetov/Reuters)

In this April 1, 2002, file photo, Mike Cole, of Jenkintown, Pa., right, performs a kick-flip over a trash can with his skateboard as tourists pose for photos in front of artist Robert Indiana's sculpture in John F. Kennedy Plaza, also known as Love Park, in Philadelphia. Granite slabs from Philadelphia's famed Love Park, a skateboarding mecca though for a long stretch an illegal one, are being shipped in 2017 to the city of Malmo, Sweden, nearly 4,000 miles away, for use in construction of a skate park there. (Photo by Douglas Bovitt/AP Photo)

Devotees wear costumes made of banana leaves as they head to church to attend mass as part of a religious festival, in honor of St. John the Baptist, also known locally as the “mud people” festival, in Aliaga town, Nueva Ecija province, north of Manila, on June 24, 2017. Farmers coated in mud paraded in Philippine villages on June 24 to mark one of the Catholic nation's most colourful religious festivals. (Photo by Noel Celis/AFP Photo)

Chinese soldiers leave after Chinese President Xi Jinping inspected troops of People's Liberation Army (PLA) Hong Kong Garrison at the Shek Kong Barracks in Hong Kong, Friday, June 30, 2017. Xi landed in Hong Kong Thursday to mark the 20th anniversary of Beijing taking control of the former British colony, accompanied by a formidable layer of security as authorities showed little patience for pro-democracy protests. (Photo by Kin Cheung/AP Photo)