Fighters of the Free Syrian Army fire an anti-aircraft weapon in the rebel-held Mashhad area in southeastern Aleppo, on December 12, 2016, as they battle Syrian government forces during an operation to retake the embattled city. The crucial battle for Aleppo entered its “final phase” after Syrian rebels retreated into a small pocket of their former bastion in the face of new army advances. The retreat leaves opposition fighters confined to just a handful of neighbourhoods in southeast Aleppo, the largest of them Sukkari and Mashhad. (Photo by AFP Photo/Stringer)

Revellers partied the night away in Leeds, UK on September 5, 2020. Leeds has been added to Public Health England's coronavirus "watchlist" and could be hit with lockdown measures after a rise in coronavirus cases in the city. (Photo by NB Press LTD/The Sun)

Buddy Mae Walker (R), 4, looks at herself in the mirror while trying on a child respirator provided by the non-profit TeamRaccoonPDX on October 6, 2020 in Portland, Oregon. We told them their grandparents sent them space suits to keep them safe, Jessica Walker said of the respirators, which the family sought out after police used tear gas near their residential street. (Photo by Nathan Howard/Getty Images)

A cow covered with foam scavenges in the waste left on the banks of the polluted Yamuna river in New Delhi on October 10, 2020. (Photo by Sajjad Hussain/AFP Photo)

A rioter smashes the window of a building on October 8, 2020 in Jakarta, Indonesia. Protesters have gathered across Indonesia after the government passed a labor law it claims will boost economic recovery needed due to coronavirus. Critics claim the bill will worsen labor conditions and environmental protections. (Photo by Ed Wray/Getty Images)

A person takes a photo of the skyline with the Shard building in the center, at sunset, from Greenwich Park in London, Tuesday, November 24, 2020. (Photo by Yui Mok/PA Wire via AP Photo)

A view of a large poster depicting Russian opposition leader Alexei Navalny behind bars with a dove freeing him from detention, by an unidentified street artist known as Harry Greb, in downtown Rome, Italy, 25 January 2021. Navalny was detained after his arrival to Moscow from Germany on 17 January 2021. A Moscow judge on 18 January ruled that he will remain in custody for 30 days following his airport arrest. Navalny urged Russians to take to the streets to protest against President Putin's rule. (Photo by Fabio Frustaci/EPA/EFE)

A Sumatran elephant calf receives medical attention at the Saree elephant conservation centre in Saree, Aceh province on February 15, 2021, following the three week-old pachyderm's rescue in Pidie district after being stuck in mud. (Photo by Chaideer Mahyuddin/AFP Photo)