A Boeing 777-300 from Swiss International Airlines lands on a foggy morning at Zurich Airport, on Friday, October 13, 2017, in Zurich, Switzerland. The high humidity renders the air vortex visible. (Photo by Christian Merz/Keystone via AP Photo)

A climber walks on the ridge beneath the eastern peak of the Gamsberg (2385 meters above sea level) near Grabs, Switzerland, Friday, October 3, 2014. (Photo by Gian Ehrenzeller/AP Photo/Keystone)

Wales' Gemma Frizelle competes in the Team Final and Individual Qualification Sub Division 2 at the Coomera Indoor Sports Centre during day seven of the 2018 Commonwealth Games in the Gold Coast, Australia on April 11, 2018. (Photo by David Gray/Reuters)

A Palestinian protester uses a sling shot to throw stones towards Israeli security forces during clashes on the Israeli border Eastern Gaza City, Friday, November 6, 2015. (Photo by Adel Hana/AP Photo)

A woman villager cleans garbage in front of her house as flood hits Tanjungsari village in Tasikmalaya, Indonesia, February 23, 2018. (Photo by Adeng Bustomi/Reuters/Antara Foto)

Pedestrians wear masks as smoke and haze from bushfires in New South Wales blankets the CBD in Sydney, Australia, 10 December 2019. The New South Wales environment department says visibility across east and southwest Sydney was at a “hazardous” level on Tuesday morning, while air quality was poor in southwest Sydney and hazardous in northwest Sydney. (Photo by Steven Saphore/EPA/EFE)

A Palestinian boy dips in a natural spring to cool off during a heat wave, amid concerns about the spread of the coronavirus disease (COVID-19), near Jericho in the Israeli-occupied West Bank on May 17, 2020. (Photo by Mohamad Torokman/Reuters)

A pedestrian wearing a form of PPE (personal protective equipment) of a perspex full-face covering, as a precautionary measure against COVID-19, walks across Oxford Street in central London on June 11, 2020, as non-essential shops prepare to re-open on June 15. Britain's current guidelines on social distancing remain at two metres (2M), but business leaders and some politicians are on Thursday calling for it to be reduced to one (1M), or one-and-a-half (1.5M) metres. (Photo by Justin Tallis/AFP Photo)