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)

In this November 19, 2015 photo, Ester Melendez feeds banana porridge to her nine-month-old daughter Dina, in Pichiquia, an Ashaninka indigenous community in Peru's Junin region. Incursions and assaults by loggers, miners, colonists and leftist guerrillas have reduced the lands of the Ashaninka people in the Peruvian Amazon, leaving many of the 97,000 members of the group malnourished, despite efforts by the government and independent organizations to help. (Photo by Rodrigo Abd/AP Photo)

India's Border Security Force (BSF) “Daredevils” motorcycle riders perform during a rehearsal for the Republic Day parade on a foggy winter morning in New Delhi January 8, 2015. India will celebrate its annual Republic Day on January 26. (Photo by Ahmad Masood/Reuters)

Iranian school girls show their hands with pro-government slogans and an anti-Israeli slogan which reads in Farsi: “Death to Israel”, during a rally in front of the former U.S. Embassy in Tehran, Iran, marking 44th anniversary of the seizure of the embassy by militant Iranian students, Saturday, November 4, 2023. (Photo by Vahid Salemi/AP Photo)

A displaced Palestinian girl holds a child as she walks at a tent camp on a rainy day, amid the ongoing conflict between Israel and Hamas, in Rafah, in the southern Gaza Strip on May 6, 2024. (Photo by Mohammed Salem/Reuters)

A boy attends the “Bloco da Lama” (Block of Mud) group during the carnival festivities, in Paraty, Brazil on February 11, 2024. (Photo by Pilar Olivares/Reuters)

Viktoriia Onopriienko, of Ukraine, performs during the rhythmic gymnastics individual all-around qualifier at the 2020 Summer Olympics, Friday, August 6, 2021, in Tokyo, Japan. (Photo by Ashley Landis/AP Photo)