Mark Delaney paints the fence outside South Hampstead High School in London, Britain on April 21, 2020. Many people have been sticking to their posts as the world fights against the COVID-19 epidemic. (Xinhua/Han Yan)

Bus driver Luis Mendez works in Montevideo, Uruguay on April 27, 2020. Many people have been sticking to their posts as the world fights against the COVID-19 epidemic. (Photo by Nicolas Celaya/Xinhua)

Peng Zhiqiang, head of the Chinese medical team in Serbia, helps a team member wear protective suit at a designated hospital for COVID-19 patients in Belgrade, Serbia, March 25, 2020. Many people have been sticking to their posts as the world fights against the COVID-19 epidemic. (Chinese medical expert team to Serbia/Handout via Xinhua)

Sanitation worker Oscar Javier carries out disinfection work in Bogota, Colombia, on April 29, 2020. Many people have been sticking to their posts as the world fights against the COVID-19 epidemic. (Photo by Jhon Paz/Xinhua)

Assistant professor Chally Lim teaches students online at home in Kuala Lumpur, Malaysia, April 28, 2020. Many people have been sticking to their posts as the world fights against the COVID-19 epidemic. (Photo by Chong Voon Chung/Xinhua)

Taxi driver Kostas Karpetopoulos poses for a photo as he works in Athens, Greece, April 22, 2020. Many people have been sticking to their posts as the world fights against the COVID-19 epidemic. (Xinhua/Marios Lolos)

Police cadet Derrick Terance Fasseu is on duty in Yaounde, Cameroon, April 23, 2020. Many people have been sticking to their posts as the world fights against the COVID-19 epidemic. (Photo by Jean Pierre Kepseu/Xinhua)

Sanitation worker Goffin Thierry works on a street in Brussels, Belgium, April 21, 2020. Many people have been sticking to their posts as the world fights against the COVID-19 epidemic. (Xinhua/Zheng Huansong)

Doctor Monica Carfora puts on protective equipment before entering the COVID-19 department at Santo Spirito Hospital in Rome, Italy, April 12, 2020. Many people have been sticking to their posts as the world fights against the COVID-19 epidemic. (Photo by Alberto Lingria/Xinhua)

Nurse Valerie Malieudje poses for a photo at her hospital in Yaounde, Cameroon, April 23, 2020. Many people have been sticking to their posts as the world fights against the COVID-19 epidemic. (Photo by Jean Pierre Kepseu/Xinhua)

Mail delivery man Dale Alexander works in London, Britain on April 21, 2020. Many people have been sticking to their posts as the world fights against the COVID-19 epidemic. (Xinhua/Han Yan)

Tuk tuk driver Uthai Bo-kae-pipat poses for a photo in Bangkok, Thailand, April 20, 2020. Many people have been sticking to their posts as the world fights against the COVID-19 epidemic. (Photo by Rachen Sageamsak/Xinhua)

Delivery man Silverio Sergio works in Paris, France, April 21, 2020. Many people have been sticking to their posts as the world fights against the COVID-19 epidemic. (Photo by Aurelien Morissard/Xinhua)

Fashion-Enter Ltd's factory production director Caroline Ash holds a top made for medical workers in London, Britain on April 17, 2020. Many people have been sticking to their posts as the world fights against the COVID-19 epidemic. (Photo by Ray Tang/Xinhua)

Ivan Ante performs maintenance work for Internet infrastructure in Quito, Ecuador, April 28, 2020. Many people have been sticking to their posts as the world fights against the COVID-19 epidemic. (Photo by Santiago Armas/Xinhua)