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)

“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)

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)

Gas-masked men of the British Machine Gun Corps with a Vickers machine gun during the first battle of the Somme, 1916. (Photo by General Photographic Agency/Getty Images)

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)

A police officer fires tear gas at protesters after the presidential election results were announced in Kisumu, Kenya on August 15, 2022. (Photo by Baz Ratner/Reuters)

SoftBank's human-like robot named “Pepper” poses for pictures in its role as a PR manager of Tottori prefecture at the prefecture speciality store in Tokyo, Japan, July 1, 2015. Pepper will work at the store until July 2, as the first workplace venue for its temporary staffing service. (Photo by Yuya Shino/Reuters)

Fans of Gimnasia de La Plata choke on tear gas during a local tournament match between Gimnasia de La Plata and Boca Juniors in La Plata, Argentina, Thursday, October 6, 2022. The match was suspended after tear gas thrown by the police outside the stadium wafted inside affecting the players as well as fans who fled to the field to avoid its effects. (Photo by Gustavo Garello/AP Photo)