A woman looks out of a dusty window after boarding a bus to be transported to see the casket of Nelson Mandela at the Union Buildings in Pretoria, South Africa, Wednesday December 11, 2013. On Thursday, December 5, 2013, Mandela died at the age of 95. (Photo by Markus Schreiber/AP Photo)

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)

People walk under Australia's iconic landmark Harbour Bridge in Sydney on April 3, 2019, as heavy fog blankets the city. Low visibility due to heavy fog affected traffic in the city and caused flight delays at the Sydney airport. (Photo by Saeed Khan/AFP Photo)

Weighing 1,500lb, Brutus the great white shark lunges at some bait off Guadalupe Island, Mexico in July 2022. (Photo by Euan Rannachan/Media Drum Images/The Times)

A student from the General Yermolov Cadet School performs with models of swords during celebrations of Maslenitsa, or Pancake Week, a pagan holiday marking the end of winter, in southern city of Stavropol, Russia, March 6, 2019. (Photo by Eduard Korniyenko/Reuters)

Street artist Irony’s mural of a young woman on Jamaica Street in Liverpool, UK on September 22, 2019. The city has recently been transformed with bold murals painted by local artists on walls and buildings. Recognisable faces including those of the Beatles, Jürgen Klopp and Stephen Hawking. (Photo by Peter Byrne/PA Wire Press Association)

Indian Hindu sadhus (holy men) from the Juna Akhara take part in a religious procession towards Sangam area, during the first “royal entry” for the Kumbh Mela in Allahabad on December 25, 2018. (Photo by Sanjay Kanojia/AFP Photo)

A Sadhu or a Hindu holy man performs to receive money from pilgrims at a makeshift shelter, before heading for an annual trip to Sagar Island for the one-day festival of “Makar Sankranti”, in Kolkata, India, January 10, 2018. (Photo by Rupak De Chowdhuri/Reuters)