A rescue helicopter is shown at the Mount Everest south base camp in Nepal a day after a huge earthquake-caused avalanche killed at least 17 people, in this photo courtesy of 6summitschallenge.com taken on April 26, 2015 and released on April 27, 2015. Rescue teams, helped by clear weather, used helicopters to airlift scores of people stranded at higher altitudes, two at a time. (Photo by Reuters/6summitschallenge.com)

A volunteer operates a remote controlled disinfection robot to disinfect a residental area amid the COVID-19 coronavirus outbreak in Wuhan in China's central Hubei province on March 16, 2020. China tightened quarantine measures for international arrivals on March 16 as the country worries about a rise in imported cases of the deadly coronavirus and anger rages online at how Europe and the United States are handling the pandemic. (Photo by AFP Photo/China Stringer Network)

A CRH train is seen passing through Nanjing South Railway Station, which is part of the Beijing-Shanghai High-Speed Railway Line, on March 27, 2011 in Nanjing, Jiangsu Province of China. The High-Speed railway line is 1,318 kilometres long, running between Beijing and Shanghai. The line will open on June 10, 2011. (Photo by ChinaFotoPress/Getty Images)

People are seen at Avalon Beach on December 18, 2020 in Sydney, Australia. A cluster of Covid-19 cases on the northern beaches of Sydney has grown to 28, prompting NSW health officials to urge residents of affected suburbs to stay home. Traffic at Sydney Airport has increased as people rush to leave the city with several states imposing quarantine restrictions for New South Wales residents. (Photo by Jenny Evans/Getty Images)

An eight-year-old St Bernard with the longest canine tongue in the world, measuring 18.58cm (7.31in) in length, as recorded by the Guinness World Records: Amazing Animals, in South Dakota, USA. (Photo by Kevin Scott Ramos/GWR/PA Wire)

People hold umbrellas as they walk past a flooded street in Taiyuan, Shanxi Province, China, July 19, 2016. (Photo by Reuters/China Daily)

People in Kathmandu joke that the face mask has now become part of the national dress – an indispensable accessory in an effort to protect themselves from the dust. Nepal has the worst air quality in the world, according to the Environmental Performance Index. (Photo by Pete Pattisson/The Guardian)

Cats gather in front of a house damaged by shelling in the town of Dokuchayevsk, south of Donetsk, February 12, 2015. (Photo by Maxim Shemetov/Reuters)