U.S. President Donald Trump holds news conference on the coronavirus outbreak at the White House in Washington, U.S., February 26, 2020. (Photo by Carlos Barria/Reuters)

Shanghai Ballet dancers wearing masks practise in a dance studio in Shanghai, China, as the country is hit by an outbreak of the novel coronavirus, February 20, 2020. (Photo by Aly Song/Reuters)

Protesters wear gas masks in the front of the Romanian Environment Ministry in Bucharest March 4, 2019, to demand better air. Dozens of people holding placards reading “Our children don't breath air anymore” gather in the front of the Environment Ministry to ask for better breathable air in Bucharest. (Photo by Daniel Mihailescu/AFP Photo)

A Muslim worshipper attends a mass prayer against COVID-19, the new coronavirus, in Dakar on March 4, 2020, after two cases were confirmed in Senegal in the previous days. Across the world, 3,155 people have died from the virus. More than 92,723 have been infected in 78 countries and territories, according to AFP's latest toll based on official sources at 1700 GMT on March 3, 2020. (Photo by John Wessels/AFP Photo)

A lady wearing a mask feeds pigeons in St James' Park, as the spread of the coronavirus disease (COVID-19) continues, London, Britain, April 5, 2020. (Photo by Henry Nicholls/Reuters)

A robot, developed by start-up firm Asimov Robotics, holds a tray with face masks and sanitizer after the two robots were launched to spread awareness about the coronavirus, in Kochi, India, March 17, 2020. (Photo by Sivaram V/Reuters)

EMT Christian Amoroso, wearing personal protective equipment (PPE), pauses while unloading COVID-19 patients at the Montefiore Medical Center Wakefield Campus on April 06, 2020 in the Bronx borough of New York City. A specialized bus known as a Medical Evacuation Transport Unit (METU), caries infected patients on stretchers and benches between hospitals. (Photo by John Moore/Getty Images)

Artists perform as people watch from the safety of their cars, during the Art Parking drive-in festival in Prague, Czech Republic, Sunday, April 26, 2020. Artists in Czech Republic are finding different ways to perform as regular theaters remain closed in an effort to stem the spread of coronavirus. (Photo by Petr David Josek/AP Photo)