Breitling Wingwalkers aircrafts perform during an aerobatic display at an air show in Zhengzhou, Henan province, China, September 25, 201. (Photo by Reuters/Stringer)

Lazar and his sister Andjelka sit by a candle in their home in the eastern Serbian town of Majdanpek, December 4, 2014. Electricity workers in Serbia struggled through snow, ice and treacherous terrain on Thursday to restore electricity to an eastern town left shivering without power, heating or running water for a fourth day. (Photo by Marko Djurica/Reuters)

Chelyabinsk Airport employees take part in an exercise to evacuate aircraft passengers showing symptoms of the 2019-nCoV pneumonia-like coronavirus on February 5, 2020. (Photo by Nail Fattakhov/TASS)

Copperhead ridden by Harry Cobden falls during the RSA Insurance Novices' Chase (Grade 1) at Cheltenham Racecourse on March 11, 2020 in Cheltenham, England. (Photo by Tom Jenkins/The Guardian)

A woman wearing a protective mask walks outside a church in Mandaluyong, east of Manila, Philippines on Sunday, February 2, 2020. The Philippines on Sunday reported the first death of a new virus outside of China, where authorities delayed the opening of schools in the worst-hit province and tightened quarantine measures in another that allow only one family member to venture out to buy supplies. (Photo by Aaron Favila/AP Photo)

Ballet dancer and performer Ashlee Montague of New York wears a gas mask while she dances in Times Square as the coronavirus disease (COVID-19) outbreak continued in Manhattan, New York City, U.S., March 18, 2020. (Photo by Andrew Kelly/Reuters)

A PSE&G utility worker watches the Navy's Blue Angels and the Air Force's Thunderbirds conduct “a collaborative salute” to honor those battling the COVID-19 pandemic with a flyover of New York and New Jersey, Tuesday, April 28, 2020, in this view from Jersey City, N.J. (Photo by Charles Sykes/Invision/AP Photo)

A staff member, wearing a face mask following the coronavirus disease (COVID-19) outbreak, looks at a robot at the venue for the World Artificial Intelligence Conference (WAIC) in Shanghai, China on July 9, 2020. (Photo by Aly Song/Reuters)