A passenger straightens his protective face mask as he waits for a train at Golden Gate metro station in Kiev during its reopening on May 25, 2020. - Ukraine's capital on Monday welcomed passengers into its subway system after over two months of lockdown imposed to slow the spread of the coronavirus. The Kiev metro, which normally transports 1.5 million people daily, remained deserted, with only 20 passengers or less in each car despite rush hour, AFP journalists saw. (Photo by Sergei SUPINSKY / AFP)

Passenger wearing protective face masks leave from a train at the Golden Gate metro station in Kiev during its reopening on May 25, 2020. - Ukraine's capital on Monday welcomed passengers into its subway system after over two months of lockdown imposed to slow the spread of the coronavirus. The Kiev metro, which normally transports 1.5 million people daily, remained deserted, with only 20 passengers or less in each car despite rush hour, AFP journalists saw. (Photo by Sergei SUPINSKY / AFP)

Passenger wearing protective face masks leave from a train at the Golden Gate metro station in Kiev during its reopening on May 25, 2020. - Ukraine's capital on Monday welcomed passengers into its subway system after over two months of lockdown imposed to slow the spread of the coronavirus. The Kiev metro, which normally transports 1.5 million people daily, remained deserted, with only 20 passengers or less in each car despite rush hour, AFP journalists saw. (Photo by Sergei SUPINSKY / AFP)

Passengers wearing protective face masks stand in a carriage at Golden Gate metro station in Kiev during its reopening on May 25, 2020. - Ukraine's capital on Monday welcomed passengers into its subway system after over two months of lockdown imposed to slow the spread of the coronavirus. The Kiev metro, which normally transports 1.5 million people daily, remained deserted, with only 20 passengers or less in each car despite rush hour, AFP journalists saw. (Photo by Sergei SUPINSKY / AFP)

A couple wearing protective face masks waits for a train on a platform of Golden Gate metro station in Kiev during its reopening on May 25, 2020. - Ukraine's capital on Monday welcomed passengers into its subway system after over two months of lockdown imposed to slow the spread of the coronavirus. The Kiev metro, which normally transports 1.5 million people daily, remained deserted, with only 20 passengers or less in each car despite rush hour, AFP journalists saw. (Photo by Sergei SUPINSKY / AFP)

An employee wearing a protective face mask checks a platform of Golden Gate metro station in Kiev during its reopening on May 25, 2020. - Ukraine's capital on Monday welcomed passengers into its subway system after over two months of lockdown imposed to slow the spread of the coronavirus. The Kiev metro, which normally transports 1.5 million people daily, remained deserted, with only 20 passengers or less in each car despite rush hour, AFP journalists saw. (Photo by Sergei SUPINSKY / AFP)

An employee wearing a protective face mask checks a platform of Golden Gate metro station in Kiev during its reopening on May 25, 2020. - Ukraine's capital on Monday welcomed passengers into its subway system after over two months of lockdown imposed to slow the spread of the coronavirus. The Kiev metro, which normally transports 1.5 million people daily, remained deserted, with only 20 passengers or less in each car despite rush hour, AFP journalists saw. (Photo by Sergei SUPINSKY / AFP)

An employee wearing a protective face mask checks a platform of Golden Gate metro station in Kiev during its reopening on May 25, 2020. - Ukraine's capital on Monday welcomed passengers into its subway system after over two months of lockdown imposed to slow the spread of the coronavirus. The Kiev metro, which normally transports 1.5 million people daily, remained deserted, with only 20 passengers or less in each car despite rush hour, AFP journalists saw. (Photo by Sergei SUPINSKY / AFP)

Passengers wearing protective face masks leave a train at Theatrical metro station in Kiev during its reopening on May 25, 2020. - Ukraine's capital on Monday welcomed passengers into its subway system after over two months of lockdown imposed to slow the spread of the coronavirus. The Kiev metro, which normally transports 1.5 million people daily, remained deserted, with only 20 passengers or less in each car despite rush hour, AFP journalists saw. (Photo by Sergei SUPINSKY / AFP)

Commuters wearing protective face masks ride on a metro train in Kiev during its reopening on May 25, 2020. - Ukraine's capital on Monday welcomed passengers into its subway system after over two months of lockdown imposed to slow the spread of the coronavirus. The Kiev metro, which normally transports 1.5 million people daily, remained deserted, with only 20 passengers or less in each car despite rush hour, AFP journalists saw. (Photo by Sergei SUPINSKY / AFP)

Commuters wearing protective face masks ride on a metro train in Kiev during its reopening on May 25, 2020. - Ukraine's capital on Monday welcomed passengers into its subway system after over two months of lockdown imposed to slow the spread of the coronavirus. The Kiev metro, which normally transports 1.5 million people daily, remained deserted, with only 20 passengers or less in each car despite rush hour, AFP journalists saw. (Photo by Sergei SUPINSKY / AFP)

Passengers wearing protective face masks leave Khreshchatyk metro station in Kiev during its reopening on May 25, 2020. - Ukraine's capital on Monday welcomed passengers into its subway system after over two months of lockdown imposed to slow the spread of the coronavirus. The Kiev metro, which normally transports 1.5 million people daily, remained deserted, with only 20 passengers or less in each car despite rush hour, AFP journalists saw. (Photo by Sergei SUPINSKY / AFP)