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)

The #8 DP Starworks Motorsports Ford Rley driven by Enzo Potolicchio, Ryan Dalziel, Alex Popow, Lucas Luhr and Allan McNish runs off the track during the Rolex 24 at Daytona International Speedway on January 28, 2012 in Daytona Beach, Florida. (Photo by John Harrelson/Getty Images)

An Indian paramilitary trooper stands guard next to a mural along a street ahead of the G20 meeting in Srinagar on May 19, 2023. (Photo by Tauseef Mustafa/AFP Photo)

English heavyweight Joe Joyce celebrates after defeating Christian Hammer during the WBC Silver Silver and WBO International Heavyweight Title fight between Joe Joyce and Christian Hammer at OVO Arena Wembley on July 02, 2022 in London, England. (Photo by Andrew Couldridge/Action Images via Reuters)

Two robotic legged squad support system (LS3) machines by the Defense Advanced Research Project Agency follow a technician during a demonstration at Joint Base Myer-Henderson Hall, Virginia, on September 10, 2012. (U.S. Marine Corps photo by Sgt. Mallory S. VanderSchans via The Atlantic)

Children watch and react as a T-Rex moves and growls in an inter-active display at Field Station Dinosaurs in Secaucus, N.J on May 25, 2012. There will be 31 types of life-sized dinosaurs displayed at the Jurassic expedition that opens Saturday, May 26. (Photo by Mel Evans/Associated Press)

Models promote a condom brand at the first Shenzhen s*x Culture Festival on September 21, 2007 in Shenzhen of Guangdong Province, China. The festival aims to increase awareness about reproductive health and popularise s*x education. (Photo by China Photos/Getty Images)