A Chinese woman wears a mask to protect from particles blown in during a sandstorm as she walks in the street on May 4, 2017 in Beijing, China. Sandstorms are common in northern China during the spring season and are caused when heavy winds from Mongolia in the north brings sand and pollutants that can blanket Chinese cities and cause air quality to deteriorate. (Photo by Kevin Frayer/Getty Images)

People enjoying the races on a wet day at Chester Racecourse on May 12, 2017 in Chester, England. (Photo by Alan Crowhurst/Getty Images)

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)

Participants perform parade in the street during Grebeg Sudiro festival on January 19, 2020 in Solo City, Central Java, Indonesia. Grebeg Sudiro festival is held as a prelude to the Chinese New Year, which falls on January 25th this year, welcoming the Year of the Rat. People bring offerings known as gunungan, including Chinese sweetcakes piled up into the shape of mountains, which are paraded in the streets followed by Chinese and Javanese performers. (Photo by Ulet Ifansasti/Getty Images)

A man wearing a hazmat suit and a mask holds a sign reading “The end is near – call grandma” at Times Square on March 14, 2020 in New York City. The World Health Organization said March 13, 2020 it was not yet possible to say when the COVID-19 pandemic, which has killed more than 5,000 people worldwide, will peak. “It's impossible for us to say when this will peak globally”, Maria Van Kerkhove, who heads the WHO's emerging diseases unit, told a virtual press conference, adding that “we hope that it is sooner rather than later”. (Photo by Johannes Eisele/AFP Photo)

An air plane takes off from the airport as air traffic is effected by the spread of the coronavirus disease (COVID-19) in Frankfurt, Germany, March 16, 2020. (Photo by Kai Pfaffenbach/Reuters)

A couple wearing face masks rides a bicycle at a park in Seoul, South Korea, Saturday, March 7, 2020. The number of infections of the COVID-19 disease spread around the globe. (Photo by Ahn Young-joon/AP Photo)

A South African police officer speaks to residents of the densely populated Alexandra township east of Johannesburg Friday, March 27, 2020. (Photo by Jerome Delay/AP Photo)