A woman wearing a scarf to cover her face looks on as she waits for a passenger bus on a smoggy morning in New Delhi, India, November 8, 2017. The Great Smog of Delhi is an ongoing severe air-pollution event in New Delhi and adjoining areas in the National Capital Territory of India, in November 2017. Air pollution at this time peaked on both PM 2.5 and PM 10 levels. It has been reported as one of the worst levels of air quality in Delhi since 1999. (Photo by Saumya Khandelwal/Reuters)

A supporter of the presidential candidate for the Honduran Opposition Alliance Against the Dictatorship for the past election, Salvador Nasralla, lies on the street in front of police officers during a demonstration against the contested re-election of President Juan Orlando Hernandez, in Tegucigalpa, Honduras on January 21, 2018. (Photo by Orlando Sierra/AFP Photo)

An armoured vehicle surrounded by Chicago cops at the time of the American depression, 1933. (Photo by Rolls Press/Popperfoto/Getty Images)

Respect, Kronotsky nature reserve, Russia. The photographer’s cat, Ryska – her name means little lynx in Russian – stands outside their cabin and with aggressive posturing warns off a fox. In winter, foxes would regularly visit the cabin searching for food. If one peered in at the window, possible when the snow was deep, Ryska would sit on the other side, fur raised, and growl. When outside, she would hold her ground. The foxes were not always frightened and so encounters could be a sort of dance. (Photo by Igor Shpilenok/Unforgettable Behaviour/NHM)

Danusorn Sdisaithaworn, 10, poses for a portrait during an annual Poy Sang Long celebration, a traditional rite of passage for boys to be initiated as Buddhist novices, while he visits a relative's house outside Mae Hong Son, Thailand, April 4, 2018. (Photo by Jorge Silva/Reuters)

Vehicles pass through the heavy fog and air pollution that cover Skopje valley in the early morning, in Skopje, The Former Yugoslav Republic of Macedonia, 14 December 2017. According to media reports, Skopje is considered one of the most polluted cities in the world. (Photo by Georgi Licovski/EPA/EFE)

People in funny costumes race down the slope in bathtubs during the 7th Bathtub race at Stoos, Switzerland, on January 19, 2019. (Photo by Urs Flueeler/EPA/EFE/Rex Features/Shutterstock)

A child dressed as a Roman centurion poses during a parade to mark the anniversary of the foundation of Rome in 753 BC, on April 23, 2017 in Rome. (Photo by Alberto Pizzoli/AFP Photo)