A man carries food supplies on a donkey to Dhalamlam Mountain in the Jafariya district of the western province of Raymah, Yemen June 2, 2016. In villages perched high on a mountain in Western Yemen, residents are a safe distance from a conflict raging throughout most of the country but have had to turn the clock back on their lifestyles by centuries. (Photo by Abduljabbar Zeyad/Reuters)

Children residents take a selfie as they wait for the police to dance, an unconventional approach to connect the police with the community in rough neighbourhoods, as part of the “Tirando Barrio” (Marking territory) programme in Saltillo, Northern Mexico September 9, 2016. T-Shirt reads “Street Dancers”. (Photo by Daniel Becerril/Reuters)

An officer wipes sweat off the face of a Chinese People's Liberation Army (PLA) honor guard soldier as they rehearse for a welcoming ceremony for New Zealand's Governor-General Sir Jerry Mateparae at the Great Hall of the People in Beijing, Tuesday, July 21, 2015. (Photo by Mark Schiefelbein/AP Photo)

A Chinese man wears a mask to protect against pollution as he waits at a red light while commuting to work in heavy smog on December 8, 2015 in Beijing, China. The Beijing government issued a 'red alert' for the first time since new standards were introduced earlier this year as the city and many parts of northern China were shrouded in heavy pollution. Levels of PM 2.5, considered the most hazardous, crossed 400 units in Beijing, lower than last week, but still nearly 20 times the acceptable standard set by the World Health Organization. The governments of more than 190 countries are meeting in Paris to set targets on reducing carbon emissions in an attempt to forge a new global agreement on climate change. (Photo by Kevin Frayer/Getty Images)

Ferencvaros's David Siger lies on the ground to defend a free kick during the UEFA Champions League Group Stage match between Ferencvarosi TC and Juventus at Puskas Arena on November 4, 2020 in Budapest, Hungary. (Photo by Bernadett Szabo/Reuters)

People watch on from Marks Park as a thunderstorm gathers off Bondi Beach on November 13, 2020 in Sydney, Australia. The Bureau of Meteorology issued a number of severe weather alerts for the region today, with a high risk of thunderstorms and hail. (Photo by Brook Mitchell/Getty Images)

A government awareness poster for wearing surgical masks is seen reflected and upside-down in the Dambovita river in Bucharest, Romania, 19 November 2020. The poster, depicting a man wearing a surgical mask, reads: “I WEAR A MASK BECAUSE I KNOW THAT ONLY TOGETHER WE WILL SUCCEED!”. As the number of COVID-19 infections increased, authorities decided that wearing a protective mask should become mandatory at all times in all public places. (Photo by Robert Ghement/EPA/EFE)

People are seen at Avalon Beach on December 18, 2020 in Sydney, Australia. A cluster of Covid-19 cases on the northern beaches of Sydney has grown to 28, prompting NSW health officials to urge residents of affected suburbs to stay home. Traffic at Sydney Airport has increased as people rush to leave the city with several states imposing quarantine restrictions for New South Wales residents. (Photo by Jenny Evans/Getty Images)