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 statue of a Japanese Akita dog named “Hachiko” wearing a face mask is seen near Shibuya Station Wednesday, April 8, 2020, in Tokyo. Japanese Prime Minister Shinzo Abe declared a state of emergency on Tuesday for Tokyo and six other prefectures to ramp up defenses against the spread of the new coronavirus. Hachiko has waited for his owner University of Tokyo Prof. Eizaburo Ueno at the same place by the station every afternoon, expecting him to return home for nearly 11 years even after Ueno's death at work. (Photo by Eugene Hoshiko/AP Photo)

Fox cubs venture out from their den under a popular boardwalk alongside Lake Ontario during the global outbreak of the coronavirus disease (COVID-19), in Toronto, Ontario, Canada on April 22, 2020. (Photo by Carlos Osorio/Reuters)

Guests watch “Trolls World Tour”, in the rain at the Four Brothers Drive In Theatre amid the coronavirus pandemic, Friday, May 15, 2020, in Amenia, N.Y. (Photo by John Minchillo/AP Photo)

A serviceman of Russia's Emergencies Ministry wearing protective gear disinfects Moscow's Leningradsky railway station on May 19, 2020, amid the COVID-19 coronavirus pandemic. (Photo by Kirill Kudryavtsev/AFP Photo)

This photo taken on May 20, 2020 shows elementary school students wearing wings to maintain social distancing amid concerns of the COVID-19 coronavirus, in a classroom in Taiyuan in China's northern Shanxi province. (Photo by AFP Photo/China Stringer Network)