A tram line named "bonde" is seen at the Santa Teresa neighbourhood, amid the coronavirus disease (COVID-19) outbreak, in Rio de Janeiro, Brazil August 25, 2020. Picture taken August 25, 2020. REUTERS/Pilar Olivares

Trams are seen in traffic, amid the outbreak of the coronavirus disease (COVID-19), in Lisbon, Portugal September 10, 2020. REUTERS/Rafael Marchante

A woman puts her mask on as she walks next to a tram, amid the outbreak of the coronavirus disease (COVID-19), in Lisbon, Portugal September 10, 2020. REUTERS/Rafael Marchante

People wearing protective face masks amid the coronavirus disease (COVID-19) outbreak wait for a tram at a public transport station in Kyiv, Ukraine September 7, 2020. REUTERS/Valentyn Ogirenko

Passengers wearing protective face masks are seen in a tram amid the coronavirus disease (COVID-19) outbreak in central Lviv, Ukraine September 3, 2020. REUTERS/Gleb Garanich

A passenger wearing a protective face mask sits in a tram amid the coronavirus disease (COVID-19) outbreak in central Lviv, Ukraine September 3, 2020. REUTERS/Gleb Garanich

Passengers wearing protective face masks sit in a tram amid the coronavirus disease (COVID-19) outbreak in central Lviv, Ukraine September 3, 2020. REUTERS/Gleb Garanich

People with and without protective face masks get off a tram at a public transport stop amid the coronavirus disease (COVID-19) outbreak in central Kyiv, Ukraine August 31, 2020. REUTERS/Gleb Garanich

People wearing protective face masks get off a tram at a public transport stop amid the coronavirus disease (COVID-19) outbreak in central Kyiv, Ukraine August 31, 2020. REUTERS/Gleb Garanich

A woman walks next to a tram, amid the outbreak of the coronavirus disease (COVID-19), in downtown Lisbon, Portugal August 28, 2020. REUTERS/Rafael Marchante

U.S. Secretary of State Mike Pompeo attends the launch the U.S.-Austria Friendship Tram at Ring tram stop in Vienna, Austria, August 14, 2020. REUTERS/Lisi Niesner/Pool

U.S. Secretary of State Mike Pompeo, U.S. ambassador to Austria Trevor Traina and Vienna's Mayor Michael Ludwig launch the U.S.-Austria Friendship Tram at Ring tram stop in Vienna, Austria, August 14, 2020. REUTERS/Lisi Niesner/Pool

U.S. Secretary of State Mike Pompeo, U.S. ambassador to Austria Trevor Traina and Vienna's Mayor Michael Ludwig launch the U.S.-Austria Friendship Tram at Ring tram stop in Vienna, Austria, August 14, 2020. REUTERS/Lisi Niesner/Pool

U.S. Secretary of State Mike Pompeo, U.S. ambassador to Austria Trevor Traina and Vienna's Mayor Michael Ludwig launch the U.S.-Austria Friendship Tram at Ring tram stop in Vienna, Austria, August 14, 2020. REUTERS/Lisi Niesner/Pool

U.S. Secretary of State Mike Pompeo attends the launch the U.S.-Austria Friendship Tram at Ring tram stop in Vienna, Austria, August 14, 2020. REUTERS/Lisi Niesner/Pool

U.S. Secretary of State Mike Pompeo, U.S. ambassador to Austria Trevor Traina and Vienna's Mayor Michael Ludwig launch the U.S.-Austria Friendship Tram at Ring tram stop in Vienna, Austria, August 14, 2020. REUTERS/Lisi Niesner/Pool

A tram goes past a sign encouraging people to wear face masks on a building , amid the spread of the coronavirus disease (COVID-19), in Manchester, Britain, August 1, 2020. REUTERS/Phil Noble

A tram goes past a sign encouraging people to wear face masks on a building , amid the spread of the coronavirus disease (COVID-19), in Manchester, Britain, August 1, 2020. REUTERS/Phil Noble

People wearing protective masks wait in a tram stop, as the city and surrounding area face local restrictions in an effort to avoid a local lockdown being forced upon the area, amid the coronavirus (COVID-19) outbreak, in Manchester, Britain, July 31, 2020. REUTERS/Molly Darlington

A woman wearing a protective face mask waits at a tram stop in Oldham, as the town faces local restrictions in an effort to avoid a local lockdown being forced upon the area amid the coronavirus disease (COVID-19) outbreak, Britain July 29, 2020. REUTERS/Phil Noble

A woman wearing a protective face mask sits on a tram in Melbourne after it became the first city in Australia to enforce mask-wearing in public as part of efforts to curb a resurgence of the coronavirus disease (COVID-19), July 23, 2020. REUTERS/Sandra Sanders

A traveler and a pilot wearing masks as they ride in the Skyway tram between terminals at IAH George Bush Intercontinental Airport amid the coronavirus disease (COVID-19) outbreak in Houston, Texas, U.S., July 21, 2020. REUTERS/Adrees Latif

Passengers wearing face masks following the coronavirus disease (COVID-19) outbreak ride a tram in Hong Kong, China July 20, 2020. REUTERS/Lam Yik

A tram remains empty during peak morning rush-hour after lockdown restrictions were implemented in response to an outbreak of the coronavirus disease (COVID-19) in Melbourne, Australia, July 10, 2020. REUTERS/Sandra Sanders

An essential worker sanitises a tram stop after lockdown restrictions were implemented in response to an outbreak of the coronavirus disease (COVID-19) in Melbourne, Australia, July 10, 2020. REUTERS/Sandra Sanders

An essential worker sanitises a tram stop after lockdown restrictions were implemented in response to an outbreak of the coronavirus disease (COVID-19) in Melbourne, Australia, July 10, 2020. REUTERS/Sandra Sanders

People wearing face masks ride a tram in front of the Airbus factory in Blagnac, near Toulouse, France, July 8, 2020. REUTERS/Nacho Doce

Passengers wear protective masks as they sit in a tram of public transport operator Verkehrsbetriebe Zurich (VBZ), as the coronavirus disease (COVID-19) outbreak continues, in Zurich, Switzerland July 6, 2020. REUTERS/Arnd Wiegmann

Passengers wear protective masks as they sit in a tram of public transport operator Verkehrsbetriebe Zurich (VBZ), as the coronavirus disease (COVID-19) outbreak continues, in Zurich, Switzerland July 6, 2020. REUTERS/Arnd Wiegmann

Passengers wear protective masks as they enter a tram of public transport operator Verkehrsbetriebe Zurich (VBZ), as the coronavirus disease (COVID-19) outbreak continues, in Zurich, Switzerland July 6, 2020. REUTERS/Arnd Wiegmann

Passengers wear protective masks as they leave a tram of public transport operator Verkehrsbetriebe Zurich (VBZ), as the coronavirus disease (COVID-19) outbreak continues, in Zurich, Switzerland July 6, 2020. REUTERS/Arnd Wiegmann

Passengers wear protective masks as they leave a tram of public transport operator Verkehrsbetriebe Zurich (VBZ), as the coronavirus disease (COVID-19) outbreak continues, in Zurich, Switzerland July 6, 2020. REUTERS/Arnd Wiegmann

Passengers wear protective masks as they leave a tram of public transport operator Verkehrsbetriebe Zurich (VBZ), as the coronavirus disease (COVID-19) outbreak continues, in Zurich, Switzerland July 6, 2020. REUTERS/Arnd Wiegmann

People ride a tram past a banner advertising the campaign of Croatian Prime Minister and the leader of the centre-right Croatian Democratic Union (HDZ) Andrej Plenkovic ahead of parliamentary elections, amid the spread of the coronavirus disease (COVID-19) in Zagrzeb, Croatia, July 3, 2020. REUTERS/Marko Djurica

A man wearing a protective mask rides a tram past a banner advertising the campaign of Croatian Prime Minister and the leader of the centre-right Croatian Democratic Union (HDZ) Andrej Plenkovic ahead of parliamentary elections, amid the spread of the coronavirus disease (COVID-19) in Zagrzeb, Croatia, July 3, 2020. REUTERS/Marko Djurica

People ride a tram past a banner advertising the campaign of Croatian Prime Minister and the leader of the centre-right Croatian Democratic Union (HDZ) Andrej Plenkovic ahead of parliamentary elections, amid the spread of the coronavirus disease (COVID-19) in Zagrzeb, Croatia, July 3, 2020. REUTERS/Marko Djurica

People ride a tram past a banner advertising the campaign of Croatian Prime Minister and the leader of the centre-right Croatian Democratic Union (HDZ) Andrej Plenkovic ahead of parliamentary elections, amid the spread of the coronavirus disease (COVID-19) in Zagrzeb, Croatia, July 3, 2020. REUTERS/Marko Djurica

People ride a tram past a banner advertising the campaign of Croatian Prime Minister and the leader of the centre-right Croatian Democratic Union (HDZ) Andrej Plenkovic ahead of parliamentary elections, amid the spread of the coronavirus disease (COVID-19) in Zagrzeb, Croatia, July 3, 2020. REUTERS/Marko Djurica

A general view shows trams in front of the headquarters of Swiss bank Credit Suisse and an office building of UBS at the Paradeplatz square in Zurich, Switzerland June 30, 2020. REUTERS/Arnd Wiegmann

Passengers board and exit a tram at Cais de Sodre station, as the outbreak of the coronavirus disease (COVID-19) continues in Lisbon, Portugal, June 26, 2020. REUTERS/Rafael Marchante

Passengers board a tram at Cais de Sodre station, as the outbreak of the coronavirus disease (COVID-19) continues in Lisbon, Portugal, June 26, 2020. REUTERS/Rafael Marchante

People wearing protective face masks are seen inside a tram at Alfama neighbourhood, amid the coronavirus disease (COVID-19) outbreak, in Lisbon, Portugal June 23, 2020. REUTERS/Rafael Marchante

Trams are seen at The intu Trafford Centre stop in Manchester, following the outbreak of the coronavirus disease (COVID-19), Manchester, Britain, June 8, 2020. REUTERS/Molly Darlington

A tram passes by The intu Trafford Centre in Manchester, following the outbreak of the coronavirus disease (COVID-19), Manchester, Britain, June 8, 2020. REUTERS/Molly Darlington

An employee of Zurich's public transport operator Verkehrsbetriebe Zuerich (VBZ) shows how to wear a protective face mask after handing them out to passengers, as a measure against the coronavirus disease (COVID-19), at a tram stop at Bellevue square in Zurich, Switzerland May 19, 2020. REUTERS/Arnd Wiegmann

An employee of Zurich?s public transport operator Verkehrsbetriebe Zuerich (VBZ) hands out protective face masks to passengers, as a measure against the coronavirus disease (COVID-19), at a tram stop at Bellevue square in Zurich, Switzerland May 19, 2020. REUTERS/Arnd Wiegmann

An employee of Zurich’s public transport operator Verkehrsbetriebe Zuerich (VBZ) hands out protective face masks to passengers, as a measure against the coronavirus disease (COVID-19), at a tram stop at Bellevue square in Zurich, Switzerland May 19, 2020. REUTERS/Arnd Wiegmann

A woman wearing a face mask waits for a tram in Manchester, following the outbreak of the coronavirus disease (COVID-19), Manchester, Britain, May 18, 2020. REUTERS/Phil Noble

A woman wearing a face mask crosses a tram line in Manchester city centre, following the outbreak of the coronavirus disease (COVID-19), Manchester, Britain May 18, 2020. REUTERS/Phil Noble

A worker crosses a tram line in Manchester city centre, following the outbreak of the coronavirus disease (COVID-19), Manchester, Britain May 18, 2020. REUTERS/Phil Noble

A man is seen on a tram in Manchester city centre, following the outbreak of the coronavirus disease (COVID-19), Manchester, Britain May 18, 2020. REUTERS/Phil Noble

A passenger wears a protective mask as he sits in a tram of public transport operator Verkehrsbetriebe Zurich (VBZ) as Switzerland eases the lockdown measures during the coronavirus disease (COVID-19) outbreak, in Zurich, Switzerland May 11, 2020. REUTERS/Arnd Wiegmann

A passenger wears a protective mask as he sits in a tram of public transport operator Verkehrsbetriebe Zurich (VBZ) as Switzerland eases the lockdown measures during the coronavirus disease (COVID-19) outbreak, in Zurich, Switzerland May 11, 2020. REUTERS/Arnd Wiegmann

Some people wear protective masks as they wait at a tram stop as Switzerland eases the lockdown measures during the coronavirus disease (COVID-19) outbreak, in Zurich, Switzerland May 11, 2020. REUTERS/Arnd Wiegmann

People wait to board a tram in Manchester city centre following the outbreak of the coronavirus disease (COVID-19), Manchester, Britain May 11, 2020. REUTERS/Phil Noble

A protection mask is added on a tram of public transport operator Verkehrsbetriebe Zurich (VBZ), as the spread of the coronavirus disease (COVID-19) continues, in Zurich, Switzerland May 8, 2020. REUTERS/Arnd Wiegmann

"Lead by example" is written on a protection mask added on a tram of public transport operator Verkehrsbetriebe Zurich (VBZ), as the spread of the coronavirus disease (COVID-19) continues, in Zurich, Switzerland May 8, 2020. REUTERS/Arnd Wiegmann

A protection mask is added on a tram of public transport operator Verkehrsbetriebe Zurich (VBZ) driving in front of the Grossmuenster church, as the spread of the coronavirus disease (COVID-19) continues, in Zurich, Switzerland May 8, 2020. REUTERS/Arnd Wiegmann

A tram platform is seen empty in Manchester, following the outbreak of the coronavirus disease (COVID-19), Manchester, Britain, May 4, 2020. REUTERS/Phil Noble

A passenger wearing a protective face mask is seen in a tram on the first day of the easing of lockdown measures, during the outbreak of the coronavirus disease (COVID-19), in Brussels, Belgium, May 4, 2020. REUTERS/Yves Herman