High-rise buildings are partly covered by heavy fog at Hong Kong's Victoria Harbour Monday, March 20, 2017. Fog blanketing Hong Kong is common in springtime and may greatly affect shipping and aviation. (Photo by Vincent Yu/AP Photo)

A koala named Lisa from Pappinbarra recovers from burns at The Port Macquarie Koala Hospital on November 29, 2019 in Port Macquarie, Australia. Volunteers from the Koala Hospital have been working alongside National Parks and Wildlife Service crews searching for koalas following weeks of devastating bushfires across New South Wales and Queensland. Koalas rescued from fire grounds have been brought back to the hospital for treatment. An estimated million hectares of land has been burned by bushfire across Australia following catastrophic fire conditions in recent weeks, killing an estimated 1000 koalas along with other wildlife. (Photo by Nathan Edwards/Getty Images)

A P-51 Mustang named “Charlotte's Chariot” from the Southern Heritage Air Foundation flies past a cloud of smoke and fire from a nearby battle reenactment during the Wings Over Houston Airshow in Houston, on Saturday, November 1, 2014. Battle reenactments are part of the yearly show held at Ellington Airport. (Photo by Kar Hlava/AP Photo/Bay Area Citizen)

This picture taken on February 1, 2015 shows participants competing in a tofu (beancurd) wrestling competition in Fogang county, south China's Guangdong province. Participants, mostly women, fight it out in an inflatable pool which is filled with nearly two tons of fresh milk and tofu, in a promotion to attract tourists for the upcoming Chinese Lunar New Year holiday. The upcoming Chinese lunar new year of the sheep, which will fall on February 19 this year, marks the biggest festival of the year in China as hundreds of millions of people journey across the country to celebrate the season with their families. (Photo by AFP Photo/Stringer)

In this January 31, 2014 file photo released by the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA), shows residents of the besieged Palestinian camp of Yarmouk, queuing to receive food supplies, in Damascus, Syria. That year, the U.N. was able to deliver food to about five percent of people in besieged areas including Yarmouk, while today estimates show the organization is reaching less than one percent. (Photo by UNRWA via AP Photo)

A dancer performs as visitors take pictures at an auto show in Tianjin, China April 28, 2016. (Photo by Reuters/Stringer)

Mayon Volcano spews ash and lava in the town of Daraga, Albay province, Philippines, 25 January 2018. Mayon volcano located in eastern Philippines and active over the last 10 days spewed fresh lava and ash while the number of evacuees exceeded 60 thousand in the face of the threat of an even more potent explosion. The Philippines, which currently has 23 active volcanoes, is situated on the so-called 'Pacific Ring of Fire', an area known for its intense seismic activity which extends from the west coast of the American continent to New Zealand, Japan, the Philippines and Indonesia. (Photo by Francis R. Malasig/EPA/EFE)

Medical staff celebrate after all patients were discharged at a temporary hospital set up to treat people with the COVID-19 coronavirus in Wuhan in China's central Hubei province on March 9, 2020. China closed most of its makeshift hospitals for coronavirus patients, some schools reopened and Disney resort staff went back to work on March 9 as normality slowly returns to the country after weeks battling the epidemic. (Photo by AFP Photo/China Stringer Network)