A man wears a gas mask as he holds a bouquet of flowers, following the outbreak of the novel coronavirus on Valentine’s Day in Hong Kong, China on February 14, 2020. (Photo by Tyrone Siu/Reuters)

Riot police fire tear gas at demonstrators during a protest against fare hikes for city buses in Sao Paulo, Brazil, January 8, 2016. Brazilian riot police on Friday fired tear gas and stun grenades to disperse a violent protest against a rise in public transport fares in the country's largest city, Sao Paulo. (Photo by Nacho Doce/Reuters)

A Citroen Ami One concept car sits on display during the media day of the Auto Shanghai 2019 motor show in Shanghai, China, 16 April 2019. The 18th Shanghai international automobile industry exhibition runs from 16 to 25 April. (Photo by Wu Hong/EPA/EFE)

Andre Krumbiegel drives in a «SIL» pointed plough through the pink fog of a smoke body in Saxony, Germany on October 2, 2019. The occasion is the forthcoming Eastern Bloc meeting on 6 October in Großhartmannsdorf, to which motor vehicles and commercial vehicles from former socialist countries can be brought, exhibited and demonstrated. Photo by Sebastian Kahnert/dpa-Zentralbild/Keystone)

People assist a woman who was exposed to tear gas by pouring milk over her face after police fired tear gas and water canon to try and disperse protesters outside Parliament on November 17, 2020 in Bangkok, Thailand. The demonstrators gathered outside parliament, on Tuesday, as the Thai government met to discuss amendments to the country's constitution. (Photo by Lauren DeCicca/Getty Images)

“The power of nature”. Magma, ash and gas erupt from Mount Etna in December 2015, rising to a height of several kilometres. Winner: Nature. (Photo by Giuseppe Mario Famiani/SIPA Contest)

A man smiles as he carries firewood he bought on a street amid ongoing fuel and cooking gas shortages in Yemen's capital Sanaa December 2, 2015. (Photo by Khaled Abdullah/Reuters)

Riot policemen launch tears gas canisters during clashes with coca growers from Yungas in La Paz, Bolivia February 21, 2017. (Photo by David Mercado/Reuters)