People in Kathmandu joke that the face mask has now become part of the national dress – an indispensable accessory in an effort to protect themselves from the dust. Nepal has the worst air quality in the world, according to the Environmental Performance Index. (Photo by Pete Pattisson/The Guardian)

Artist Kong Ning wears a wedding dress made from respirators to highlight concerns about air quality and pollution in Beijing, China on December 1, 2015. (Photo by Luo Xiaoguang/Xinhua Press/Corbis)

Recruits who earned a place in the Motivation Platoon struggle through water and muck on their way to becoming a Marine or going into some other line of work, October 7, 1971. (Photo by Eddie Adams/AP Photo)

A giant biodegradable landart painting entitled “Vers l'equilibre” (Towards balance) by French-Swiss artist Saype is pictured near the summit of the Grand Chamossaire mountain, above the alpine resort of Villars-sur-Ollon, Switzerland, Wednesday, July 06, 2022. Extending over an area of 2500 square meters, this fresco was created using biodegradable pigments made out of charcoal, chalk, water and milk proteins. (Photo by Valentin Flauraud/Keystone via AP Photo)

One of the busiest areas in Birmingham, United Kingdom last night was Ludgate Hill in the city's Jewellery Quarter. Brits enjoying the hottest August day for almost 20 years spilled out of packed pubs on August 7, 2020 after sunbathing on beaches around the country as the mercury rose to 36.4C. (Photo by SnapperSK/The Sun)

Miniscule larvae carve winding tunnels as they eat through small leaves in a small forest near the town of Velbert in western Germany in July 2022. The hungry green sawfly larvae measure just three millimetres in length and are difficult to spot on the leaves of the beech tree unless up close. (Photo by Christian Brockes/Solent News)

Racegoers shield themselves from the rain and wind at the Fairyhouse Easter Festival in Fairyhouse, Co. Meath, Ireland on April 10, 2023. (Photo by Morgan Treacy/Inpho)

A government awareness poster for wearing surgical masks is seen reflected and upside-down in the Dambovita river in Bucharest, Romania, 19 November 2020. The poster, depicting a man wearing a surgical mask, reads: “I WEAR A MASK BECAUSE I KNOW THAT ONLY TOGETHER WE WILL SUCCEED!”. As the number of COVID-19 infections increased, authorities decided that wearing a protective mask should become mandatory at all times in all public places. (Photo by Robert Ghement/EPA/EFE)