Vehicles pass through the heavy fog and air pollution that cover Skopje valley in the early morning, in Skopje, The Former Yugoslav Republic of Macedonia, 14 December 2017. According to media reports, Skopje is considered one of the most polluted cities in the world. (Photo by Georgi Licovski/EPA/EFE)

As an airliner prepares to land, a bird takes off at the Gravelly Point park near Reagan National Airport in Arlington, Va. on December 23, 2018. (Photo by Michael S. Williamson/The Washington Post)

Aerial view of pond cypress at Qinglongwan Forest Park near Ningguo, China on November 26, 2017. (Photo by Imaginechina/Rex Features/Shutterstock)

A man watches the huge waves which brakes at the Paseo Nuevo's promenade in San Sebastian, Basque Country, Spain on 11 January 2016 where the wind has reached to 90 km/h and have been registred waves of eight kilometres due to the bad weather. (Photo by Juan Herrero/EPA/EFE)

The buildings of the banking district are seen through thousands of rain drops on a glass railing in central Frankfurt, Germany, Wednesday, January 11, 2017. (Photo by Michael Probst/AP Photo)

Naked footballers participate in a Germany v Netherlands soccer match in protest against what they say is increasing commercialization of professional football, in Wuppertal, Germany on September 6, 2020. (Photo by Leon Kuegeler/Reuters)

A man runs on a small road in the outskirts of Frankfurt, Germany, before sunrise on Tuesday, September 1, 2020. (Photo by Michael Probst/AP Photo)

Models present creations during the 8ON8 PRESENTED BY GQ China catwalk show at London Fashion Week Mens Spring/Summer 2020 in London, Britain, January 5, 2020. (Photo by Henry Nicholls/Reuters)