A worker wearing a protective face mask and gloves cleans the floor at Chit Lom skytrain station in Bangkok, as the spread of the coronavirus disease (COVID-19) continues, Bangkok, Thailand, April 13, 2020. REUTERS/Jorge Silva

A pedestrian area connecting the skytrain BTS with shopping malls is seen empty after the government shut down all the shopping centers in the country due to the coronavirus disease (COVID-19) outbreak, in Bangkok, Thailand March 22, 2020. REUTERS/Jorge Silva

A couple travel in the skytrain wearing protective masks due to the coronavirus outbreak in Bangkok, Thailand March 9, 2020. Picture taken March 9, 2020. REUTERS/Jorge Silva

Sparsely occupied skytrains pass through Jewel, the retail complex of Changi Airport, amid a decline in tourism following the coronavirus disease (COVID-19) outbreak in Singapore, March 7, 2020. Picture taken March 7, 2020. REUTERS/Loriene Perera

A girl wearing a protective mask plays a violin at the entrance of the skytrain in Bangkok, Thailand, February 26, 2020. REUTERS/Jorge Silva

Commuters wearing protective masks ride the skytrain in Bangkok, Thailand, February 26, 2020. REUTERS/Jorge Silva

Commuters wearing protective masks ride the skytrain in Bangkok, Thailand, February 26, 2020. REUTERS/Jorge Silva

A woman wearing a protective mask waits for the skytrain in Bangkok, Thailand, February 26, 2020. REUTERS/Jorge Silva

A woman wearing a protective mask waits for the skytrain in Bangkok, Thailand, February 26, 2020. REUTERS/Jorge Silva

A woman wearing a protective mask waits for the skytrain in Bangkok, Thailand, February 26, 2020. REUTERS/Jorge Silva

A woman wearing a protective mask waits for the skytrain in Bangkok, Thailand, February 26, 2020. REUTERS/Jorge Silva

A woman wearing a protective mask waits for the skytrain in Bangkok, Thailand, February 26, 2020. REUTERS/Jorge Silva

A woman wearing a protective mask waits for the skytrain in Bangkok, Thailand, February 26, 2020. REUTERS/Jorge Silva

A woman wearing a protective mask waits for the skytrain in Bangkok, Thailand, February 26, 2020. REUTERS/Jorge Silva

A woman wearing a protective mask waits for the skytrain in Bangkok, Thailand, February 26, 2020. REUTERS/Jorge Silva

Commuters wearing protective masks walk inside the Skytrain BTS in Bangkok, Thailand February 24, 2020. REUTERS/Chalinee Thirasupa

Commuters wearing protective masks walk inside the Skytrain BTS in Bangkok, Thailand February 24, 2020. REUTERS/Chalinee Thirasupa

A commuter waits for a train wearing a protective mask at the Skytrain BTS in Bangkok, Thailand February 24, 2020. REUTERS/Chalinee Thirasupa

A commuter waits for a train wearing a protective mask at the Skytrain BTS in Bangkok, Thailand February 24, 2020. REUTERS/Chalinee Thirasupa

People ride in the skytrain BTS wearing protective masks in Bangkok, Thailand February 13, 2020. Picture taken February 13, 2020. REUTERS/Jorge Silva

People ride in the skytrain BTS wearing protective masks in Bangkok, Thailand February 13, 2020. Picture taken February 13, 2020. REUTERS/Jorge Silva

People ride in the skytrain BTS wearing protective masks in Bangkok, Thailand February 13, 2020. Picture taken February 13, 2020. REUTERS/Jorge Silva

People ride in the skytrain BTS wearing protective masks in Bangkok, Thailand February 13, 2020. Picture taken February 13, 2020. REUTERS/Jorge Silva

A woman poses next to hearts celebrating Valentine's Day in a skytrain BTS station in Bangkok, Thailand February 13, 2020. Picture taken February 13, 2020. REUTERS/Jorge Silva

A woman stands next to hearts celebrating Valentine's Day in a skytrain BTS station in Bangkok, Thailand February 13, 2020. Picture taken February 13, 2020. REUTERS/Jorge Silva

A woman removes her protective masks to take a selfie in front of hearts celebrating Valentine's Day in a skytrain BTS station in Bangkok, Thailand February 13, 2020. Picture taken February 13, 2020. REUTERS/Jorge Silva

Passengers wear protective face masks as they stand on the escalator at a Skytrain station in Bangkok, Thailand, February 7, 2020. REUTERS/Athit Perawongmetha

Officials distribute protective face masks to people near a Skytrain station in Bangkok, Thailand February 7, 2020. REUTERS/Athit Perawongmetha

Officials distribute protective face masks to people near a Skytrain station in Bangkok, Thailand February 7, 2020. REUTERS/Athit Perawongmetha

People wear protective masks during rush hour inside the BTS skytrain in Bangkok, Thailand February 5, 2020. REUTERS/Chalinee Thirasupa

People wear protective masks during rush hour inside the BTS skytrain in Bangkok, Thailand February 5, 2020. REUTERS/Chalinee Thirasupa

A skytrain which connects the various terminals in Changi Airport is seen inside Jewel in Singapore, April 11, 2019. REUTERS/Feline Lim

Damkerng Mungthanya, who is a blind teacher, receives help by a security guard at a skytrain station in Bangkok, Thailand, February 12, 2019. Picture taken February 12, 2019. REUTERS/Athit Perawongmetha

Damkerng Mungthanya, who is a blind teacher, rides a skytrain in Bangkok, Thailand, February 12, 2019. Picture taken February 12, 2019. REUTERS/Athit Perawongmetha

Damkerng Mungthanya, who is a blind teacher, receives help by a security guard at a skytrain station in Bangkok, Thailand, February 14, 2019. Picture taken February 14, 2019. REUTERS/Athit Perawongmetha

Damkerng Mungthanya, who is a blind teacher, waits for help at a skytrain station in Bangkok, Thailand, February 14, 2019. Picture taken February 14, 2019. REUTERS/Athit Perawongmetha

Damkerng Mungthanya, who is a blind teacher, rides a skytrain in Bangkok, Thailand, February 15, 2019. Picture taken February 15, 2019. REUTERS/Athit Perawongmetha

A pigeon flies as a Skytrain travels among buildings in Bangkok, Thailand November 12, 2018. REUTERS/Soe Zeya Tun

A man wearing a cap rides the skytrain in Bangkok, Thailand September 20, 2018. REUTERS/Jorge Silva

A girl walks past a Skytrain (Bangkok Mass Transit System) construction site in Bangkok, Thailand May 13, 2018. Picture taken May 13, 2018. REUTERS/Soe Zeya Tun

Cars pass a Skytrain (Bangkok Mass Transit System) construction site in Bangkok, Thailand May 13, 2018. REUTERS/Soe Zeya Tun

Cars pass a Skytrain (Bangkok Mass Transit System) construction site in Bangkok, Thailand May 13, 2018. REUTERS/Soe Zeya Tun

People walk past a Skytrain (Bangkok Mass Transit System) construction site in Bangkok, Thailand May 13, 2018. REUTERS/Soe Zeya Tun

Passengers are seen during rush hour at a skytrain station in Bangkok, Thailand, October 30, 2017. Thailand officially ended a year of mourning for its late King Bhumibol Adulyadej on Monday, marking a return to colors for some after a monotone year during which many wore black from head-to-toe out of respect for their revered monarch. REUTERS/Athit Perawongmetha

Passengers are seen during rush hour at a skytrain station in Bangkok, Thailand, October 30, 2017. Thailand officially ended a year of mourning for its late King Bhumibol Adulyadej on Monday, marking a return to colors for some after a monotone year during which many wore black from head-to-toe out of respect for their revered monarch. REUTERS/Athit Perawongmetha TPX IMAGES OF THE DAY

Passengers are seen during rush hour at a skytrain station in Bangkok, Thailand, October 30, 2017. Thailand officially ended a year of mourning for its late King Bhumibol Adulyadej on Monday, marking a return to colors for some after a monotone year during which many wore black from head-to-toe out of respect for their revered monarch. REUTERS/Athit Perawongmetha

Passengers are seen during rush hour at a skytrain station in Bangkok, Thailand, October 30, 2017. Thailand officially ended a year of mourning for its late King Bhumibol Adulyadej on Monday, marking a return to colors for some after a monotone year during which many wore black from head-to-toe out of respect for their revered monarch. REUTERS/Athit Perawongmetha

Passengers are seen during rush hour at a skytrain station in Bangkok, Thailand, October 30, 2017. Thailand officially ended a year of mourning for its late King Bhumibol Adulyadej on Monday, marking a return to colors for some after a monotone year during which many wore black from head-to-toe out of respect for their revered monarch. REUTERS/Athit Perawongmetha

A woman walks outside a BTS station (Mass Transit System), also known as the skytrain, in Bangkok, Thailand June 16, 2017. REUTERS/Jorge Silva

A passenger rides the skytrain in Bangkok, Thailand, September 19, 2016. Picture taken September 19, 2016. REUTERS/Athit Perawongmetha

Passengers stand next to a GrabTaxi advertisement as they wait for skytrain at a station in Bangkok, Thailand, June 2, 2016. This logo has been updated and is no longer in use. REUTERS/Athit Perawongmetha

A passenger stands next to a GrabTaxi advertisement as he waits for skytrain at a station in Bangkok, Thailand, June 2, 2016. This logo has been updated and is no longer in use. REUTERS/Athit Perawongmetha

Passengers stand next to a GrabTaxi advertisement as they wait for skytrain at a station in Bangkok, Thailand, June 2, 2016. This logo has been updated and is no longer in use. REUTERS/Athit Perawongmetha

Passengers stand next to a GrabTaxi advertisement as they wait for skytrain at a station in Bangkok, Thailand, June 2, 2016. This logo has been updated and is no longer in use. REUTERS/Athit Perawongmetha

A security guard keeps watch on a skytrain platform in Bangkok, Thailand, May 20, 2015. REUTERS/Chaiwat Subprasom

Passengers use their mobile phones on a skytrain in Bangkok June 20, 2014. Thailand's telecoms sector is fast emerging as the first economic casualty of an interventionist junta in a country that has swung between democratic and military rule more times than any other nation in Southeast Asia. The government led by General Prayuth Chan-ocha halted an auction of 4G bandwidth last week after giving its blessings to the tender in May when it came to power. Telecoms analysts say the suspension could lead to $4 billion in investment and revenue losses in a sector that accounts for a tenth of Thailand's GDP. A prolonged delay could also cause mobile service disruptions. Picture taken June 20, 2014. REUTERS/Athit Perawongmetha (THAILAND - Tags: BUSINESS TELECOMS POLITICS)

Passengers use their mobile phones on a skytrain in Bangkok June 20, 2014. Thailand's telecoms sector is fast emerging as the first economic casualty of an interventionist junta in a country that has swung between democratic and military rule more times than any other nation in Southeast Asia. The government led by General Prayuth Chan-ocha halted an auction of 4G bandwidth last week after giving its blessings to the tender in May when it came to power. Telecoms analysts say the suspension could lead to $4 billion in investment and revenue losses in a sector that accounts for a tenth of Thailand's GDP. A prolonged delay could also cause mobile service disruptions. Picture taken June 20, 2014. REUTERS/Athit Perawongmetha (THAILAND - Tags: BUSINESS TELECOMS POLITICS)

An history enthusiast takes a picture of U.S. Air Force C-47 Skytrain aircraft as they fly over the city of Carentan, on the Normandy coast June 4, 2014. Some 18 heads of state will attend ceremonies bringing together 3,000 veterans along France's northern coast where Allied forces landed on June 6, 1944 in a seaborne invasion that sped up the defeat of Nazi Germany in World War Two. REUTERS/Pascal Rossignol (FRANCE - Tags: CONFLICT ANNIVERSARY POLITICS)

The airport skytrain service passes the control tower at Singapore's Changi Airport August 20, 2013. Singapore's ambitious project to double its air passenger handling capacity by the mid-2020s is set to extend its lead over neighbours like Kuala Lumpur, Bangkok and Jakarta, whose airports are struggling with congestion and construction delays. Changi, Southeast Asia's biggest and most popular international airport, is keen to seize a greater share of a boom in regional traffic, mindful of competitors' plans to grow into international hubs. Picture taken August 20, 2013. To match story ASIA-AIRPORTS/SINGAPORE REUTERS/Edgar Su (SINGAPORE - Tags: BUSINESS TRANSPORT)

A passenger waits for a skytrain during rush hour at a station in Bangkok July 8, 2013. REUTERS/Athit Perewongmetha (THAILAND - Tags: SOCIETY TRANSPORT)