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)

A man looks inside an overturned truck after an accident along the road between Nouahibou and Nouakchott, Mauritania December 3, 2009. (Photo by Rafael Marchante/Reuters)

Rugby Union, Hong Kong Sevens, Hong Kong Stadium on April 9, 2016: A fan wearing a mask is hugged. (Photo by Bobby Yip/Reuters)

Greek actress Xanthi Georgiou, playing the role of the High Priestess, lights up the torch during the flame lighting ceremony for the Beijing 2022 Winter Olympics at the Ancient Olympia archeological site, birthplace of the ancient Olympics in southern Greece on October 18, 2021. The Olympic flame will once again be lit in an empty stadium on Ovtober 18, 2021, as it starts its truncated journey to Beijing for the Winter Games in February. Like the ceremony in March 2020 to light the flame for Tokyo, and like those Games, which were put back a year, Monday's ceremony is a victim of coronavirus restrictions. (Photo by Aris Messinis/AFP Photo)

Three Japanese tourists had to abandon plans to drive to Stradbroke Island off the Queensland coast when their hire car became bogged in mangrove mud, on March 15, 2012 near Stradbroke Island, Australia. (Photo by Chris McCormack/Fairfax Media).

A Geminid meteor streaks diagonally across the sky against a field of star trails behind one of the peaks of the Seven Sisters rock formation in this long exposure early December 14, 2007 in the Valley of Fire State Park in Nevada. The meteor display, known as the Geminid meteor shower because it appears to radiate from near the star Castor in the constellation Gemini, is thought to be the result of debris cast off from an asteroid-like object called 3200 Phaethon. The shower is visible every December. (Photo by Ethan Miller/Getty Images)

Film technicians at Pinewood Studios set up a miniature air crash sequence for the Jack Gold film “The Medusa Touch”, using scale models of a Boeing 747 and a skyscraper. (Photo by Alan F. Davis/Keystone/Getty Images). 9th August 1977

A worker looks at an old soviet tank T-34 (L) as he fixes military vehicle (R) at a Phaeton museum in Zaporizhia, Ukraine, August 11, 2015. The museum stopped the restoration works of their collection of about 120 retro autos and motorcycles to help the Ukrainian army to restore military vehicles and equipment which will be used in the conflict in Ukraine eastern regions. (Photo by Gleb Garanich/Reuters)