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)

Protestors from the Extinction Rebellion march on day six of protests stopping traffic in the city district of Melbourne, Australia on October 12, 2019. (Photo by ydney Low/ZUMA Wire/Rex Features/Shutterstock)

Hirari Ikeda, a well-known Harajuku street fashion personality, on the street in Shibuya. (Photo by Tokyo Fashion)

A pair of ice climbers have been snapped in front of a stunning aurora. Mike Stuart and Takeshi Tani were climbing the Athabasca Glacier in Alberta, Canada, when the aurora lit up the nights sky. They were photographed by famed night-time photographer Paul Zizka, who specialises in photographing auroras in some of Canadas most beautiful parks. (Photo by Paul Zizka/Caters News)

To mark Halloween, 150 teens descended upon a swimming pool in Essex to help mobile network giffgaff recreate the famous Tomatina tomato fight... only this time, with blood and guts. Different takes #giffgaffguts. On October 18, 2013 in Dagenham, England. (Photo by Dave J. Hogan/Stringer for giffgaff)

A model presents a creation by Colombian brand Elena Plus Clothing at Colombiamoda during Medellin's fashion week in Itagui municipality near Medellin, Antioquia department, Colombia, on July 24, 2017. Colombiamoda will take place between the 24th and 27th of July. (Photo by Joaquin Sarmiento/AFP Photo)

A chained male monkey in a costume and wearing a toy mask performs at a street in Depok, West Java, Indonesia, 30 September 2021. A performing monkey in a street, known as “Topeng Monyet” (lit. Monkey Mask), is a popular form of cheap entertainment in Indonesia, especially on the island of Java. (Photo by Adi Weda/EPA/EFE)

In this January 25, 2013 photo, snake handler Saintilus Resilus holds a snake in front of his lips as he trains the snake to recognize his smell as he prepares for his street performances during the pre-Lenten Carnival season, at his home in Petionville, Haiti. Resilus sees himself as something of a performance artist, showing off with snakes and other animals that Haitians don't see every day, earning tips from impromptu audiences. (Photo by Dieu Nalio Chery/AP Photo via Matt Dayhoff)