A commuter at Rome's main train station Termini wears a mask, amid the coronavirus disease (COVID-19) outbreak, in Rome, Italy, February 22, 2021. REUTERS/Guglielmo Mangiapane

A commuter at Rome's main train station Termini wears a mask, amid the coronavirus disease (COVID-19) outbreak, in Rome, Italy, February 22, 2021. REUTERS/Guglielmo Mangiapane

Commuters at Rome's main train station Termini wear masks, amid the coronavirus disease (COVID-19) outbreak, in Rome, Italy, February 22, 2021. REUTERS/Guglielmo Mangiapane

A commuter at Rome's main train station Termini wears a mask, amid the coronavirus disease (COVID-19) outbreak, in Rome, Italy, February 22, 2021. REUTERS/Guglielmo Mangiapane

Commuters at Rome's main train station Termini wear masks, amid the coronavirus disease (COVID-19) outbreak, in Rome, Italy, February 22, 2021. REUTERS/Guglielmo Mangiapane

Commuters walk on a railway platform after disembarking from a train amidst the spread of the coronavirus disease (COVID-19) in Mumbai, India, February 9, 2021. REUTERS/Francis Mascarenhas

Passengers wear face masks as they wait for an S-Bahn commuter train on the platform at Friedrichstrasse station during lockdown amid the coronavirus disease (COVID-19) pandemic, in Berlin, Germany February 5, 2021. REUTERS/Fabrizio Bensch

A man wearing a protective mask gives a plastic bag containing his air-sample to be tested using GeNose C19 (GeNose), a coronavirus disease (COVID-19) detection tool, at a train station in Jakarta, Indonesia, February 3, 2021. REUTERS/Ajeng Dinar Ulfiana

A healthcare worker holds a plastic bag containing a commuter's air-sample to be tested for the coronavirus disease (COVID-19) using GeNose C19 (GeNose), a COVID-19 detection tool, at a train station in Jakarta, Indonesia, February 3, 2021. REUTERS/Ajeng Dinar Ulfiana

A woman wearing a protective mask blows a plastic bag as she takes her air-sample to be tested for the coronavirus disease (COVID-19) using GeNose C19 (GeNose), a COVID-19 detection tool, at a train station in Jakarta, Indonesia, February 3, 2021. REUTERS/Ajeng Dinar Ulfiana

Commuters wearing protective masks blow a plastic bag as they take their air-sample to be tested using GeNose C19 (GeNose), a coronavirus disease (COVID-19) detection tool, at a train station in Jakarta, Indonesia, February 3, 2021. REUTERS/Ajeng Dinar Ulfiana

Commuters wearing protective masks hold plastic bags containing their air-samples to be tested using GeNose C19 (GeNose), a coronavirus disease (COVID-19) detection tool, at a train station in Jakarta, Indonesia, February 3, 2021. REUTERS/Ajeng Dinar Ulfiana

A healthcare worker tests an air-sample of a commuter using GeNose C19 (GeNose), a coronavirus disease (COVID-19) detection tool, at a train station in Jakarta, Indonesia, February 3, 2021. REUTERS/Ajeng Dinar Ulfiana

Commuters cross a zebra crossing, amid the coronavirus disease (COVID-19) pandemic in Seoul, South Korea, February 3, 2021. REUTERS/Kim Hong-Ji

People wearing protective face masks wait in queues to buy train tickets at the Chhatrapati Shivaji Maharaj Terminus (CSMT) railway station after authorities resumed suburban train services for all commuters after it was shut down to prevent the spread of the coronavirus disease (COVID-19), in Mumbai, India, February 1, 2021. Picture taken February 1, 2021. REUTERS/Hemanshi Kamani

Commuters wearing protective face masks travel in a suburban train after authorities resumed the train services for all commuters after it was shut down to prevent the spread of the coronavirus disease (COVID-19), in Mumbai, India, February 1, 2021. REUTERS/Hemanshi Kamani

Commuters wearing protective face masks travel in a suburban train after authorities resumed the train services for all commuters after it was shut down to prevent the spread of the coronavirus disease (COVID-19), in Mumbai, India, February 1, 2021. REUTERS/Hemanshi Kamani

Women covering their faces with protective masks commute in a suburban train after authorities resumed the train services for all commuters after it was shut down to prevent the spread of the coronavirus disease (COVID-19) in Mumbai, India, February 1, 2021. REUTERS/Hemanshi Kamani

People travel in a suburban train after authorities resumed the train services for all commuters after it was shut down to prevent the spread of the coronavirus disease (COVID-19), in Mumbai, India, February 1, 2021. REUTERS/Hemanshi Kamani

People covering their faces with protective masks disembark a suburban train after authorities resumed the train services for all commuters after it was shut down to prevent the spread of the coronavirus disease (COVID-19) at a railway station in Mumbai, India, February 1, 2021. REUTERS/Hemanshi Kamani

People covering their faces with protective masks disembark a suburban train after authorities resumed the train services for all commuters after it was shut down to prevent the spread of the coronavirus disease (COVID-19), at a railway station in Mumbai, India, February 1, 2021. REUTERS/Hemanshi Kamani

Commuters board and disembark a train at a railway station in Kolkata, India, February 1, 2021. REUTERS/Ranita Roy

People wearing face masks commute in a subway station during morning rush hour, following the coronavirus disease ( COVID-19) outbreak, in Beijing, China January 20, 2021. REUTERS/Tingshu Wang

People wearing face masks commute in a subway station during morning rush hour, following the coronavirus disease ( COVID-19) outbreak, in Beijing, China January 20, 2021. REUTERS/Tingshu Wang

People wearing face masks commute in a subway station during morning rush hour, following the coronavirus disease ( COVID-19) outbreak, in Beijing, China January 20, 2021. REUTERS/Tingshu Wang

People wearing face masks commute in a subway station during morning rush hour, following the coronavirus disease ( COVID-19) outbreak, in Beijing, China January 20, 2021. REUTERS/Tingshu Wang

People wearing face masks commute in a subway station during morning rush hour, following the coronavirus disease ( COVID-19) outbreak, in Beijing, China January 20, 2021. REUTERS/Tingshu Wang

People wearing face masks commute in a subway station during morning rush hour, following the coronavirus disease ( COVID-19) outbreak, in Beijing, China January 20, 2021. REUTERS/Tingshu Wang

People wearing face masks commute in a subway station during morning rush hour, following the coronavirus disease ( COVID-19) outbreak, in Beijing, China January 20, 2021. REUTERS/Tingshu Wang

People wearing face masks commute in a subway station during morning rush hour, following the coronavirus disease ( COVID-19) outbreak, in Beijing, China January 20, 2021. REUTERS/Tingshu Wang

People wearing face masks commute in a subway station during morning rush hour, following the coronavirus disease ( COVID-19) outbreak, in Beijing, China January 20, 2021. REUTERS/Tingshu Wang

People commute at the main train station during a lockdown following a soaring of coronavirus disease (COVID-19) in Porto, Portugal January 18, 2021. REUTERS/Violeta Santos Moura

People commute at the main train station during a lockdown following a soaring of coronavirus disease (COVID-19) in Porto, Portugal January 18, 2021. REUTERS/Violeta Santos Moura

People commute using the cableway during a lockdown following a soaring of coronavirus disease (COVID-19) in Porto, Portugal January 18, 2021. REUTERS/Violeta Santos Moura

People commute during a lockdown following a soaring of coronavirus disease (COVID-19) in Porto, Portugal January 18, 2021. REUTERS/Violeta Santos Moura

A commuter waits at the main train station during a lockdown following a soaring of coronavirus disease (COVID-19) in Porto, Portugal January 18, 2021. REUTERS/Violeta Santos Moura

Commuters arrive to the main train station during a lockdown following a soaring cases of coronavirus disease (COVID-19) in Porto, Portugal January 18, 2021. REUTERS/Violeta Santos Moura

Commuters get off the train at rush hour, amid the coronavirus disease (COVID-19) outbreak, at Canning Town underground station in London, Britain, January 18, 2021. REUTERS/Hannah McKay

Commuters take the train at rush hour, amid the coronavirus disease (COVID-19) outbreak, at Canning Town underground station in London, Britain, January 18, 2021. REUTERS/Hannah McKay

A commuter walks at rush hour, amid the coronavirus disease (COVID-19) outbreak, at Canning Town underground station in London, Britain, January 18, 2021. REUTERS/Hannah McKay

Commuters take the train at rush hour, amid the coronavirus disease (COVID-19) outbreak, at Canning Town underground station in London, Britain, January 18, 2021. REUTERS/Hannah McKay

Commuters walk at rush hour, amid the coronavirus disease (COVID-19) outbreak, at Canning Town underground station in London, Britain, January 18, 2021. REUTERS/Hannah McKay

Commuters head to take the train at rush hour, amid the coronavirus disease (COVID-19) outbreak, at Canning Town underground station in London, Britain, January 18, 2021. REUTERS/Hannah McKay

A commuter gets on a train, amid the coronavirus disease (COVID-19) outbreak, at Canning Town underground station in London, Britain, January 18, 2021. REUTERS/Hannah McKay

Commuters take the train at rush hour, amid the coronavirus disease (COVID-19) outbreak, in London, Britain, January 18, 2021. REUTERS/Hannah McKay

A commuter waits for the train, amid the coronavirus disease (COVID-19) outbreak, at Canning Town underground station in London, Britain, January 18, 2021. REUTERS/Hannah McKay

A commuter gets off a train at rush hour, amid the coronavirus disease (COVID-19) outbreak, at Canning Town underground station in London, Britain, January 18, 2021. REUTERS/Hannah McKay

Commuters take the train at rush hour, amid the coronavirus disease (COVID-19) outbreak, at Canning Town underground station in London, Britain, January 18, 2021. REUTERS/Hannah McKay

Commuters take the train at rush hour, amid the coronavirus disease (COVID-19) outbreak, at Canning Town underground station in London, Britain, January 18, 2021. REUTERS/Hannah McKay

Commuters wait for the train at rush hour, amid the coronavirus disease (COVID-19) outbreak, at Canning Town underground station in London, Britain, January 18, 2021. REUTERS/Hannah McKay

A commuter walks at rush hour, amid the coronavirus disease (COVID-19) outbreak, at Canning Town underground station in London, Britain, January 18, 2021. REUTERS/Hannah McKay

A commuter gets on a train, amid the coronavirus disease (COVID-19) outbreak, at Canning Town underground station in London, Britain, January 18, 2021. REUTERS/Hannah McKay

A commuter waits for the train, amid the coronavirus disease (COVID-19) outbreak, at Canning Town underground station in London, Britain, January 18, 2021. REUTERS/Hannah McKay

People commuting are silhouetted on a cold winter day in Seoul, South Korea, January 13, 2021. REUTERS/Kim Hong-Ji

People commute at the Vauxhall tube station amid the coronavirus disease (COVID-19) outbreak, in London, Britain January 12, 2021. REUTERS/Henry Nicholls

Passengers commute at the Victoria tube station amid the coronavirus disease (COVID-19) outbreak, in London, Britain January 12, 2021. REUTERS/Henry Nicholls

A man looks on amongst commuters at the Vauxhall tube station amid the coronavirus disease (COVID-19) outbreak, in London, Britain January 12, 2021. REUTERS/Henry Nicholls

A man looks up while commuting at the Vauxhall tube station amid the coronavirus disease (COVID-19) outbreak, in London, Britain January 12, 2021. REUTERS/Henry Nicholls

A woman wearing a face mask stands on a platform as people commute at the Victoria tube station amid the coronavirus disease (COVID-19) outbreak, in London, Britain January 12, 2021. REUTERS/Henry Nicholls

People commute at the Victoria tube station amid the coronavirus disease (COVID-19) outbreak, in London, Britain January 12, 2021. REUTERS/Henry Nicholls