In this photograph taken on February 18, 2016, Pakistani children ride on swings in the predominantly Pashtun Korangi District of Karachi. In a rundown district of Karachi, Rabia balks at a neighbour's proposal to vaccinate her children, demonstrating one of the biggest hurdles to eradicating polio in Pakistan by the end of the year: confused and frightened parents. (Photo by Asif Hassan/AFP Photo)

An arrow-head discovered in 2006 by Archaeologists of the University of Cambridge Archaeological Unit, is displayed by one of the team uncovering Bronze Age wooden houses, preserved in silt, from a quarry near Peterborough, Britain, January 12, 2016. Archaeologists said on Tuesday they had discovered what were believed to be the best-preserved Bronze Age dwellings ever found in Britain, providing an extraordinary insight into prehistoric life from 3,000 years ago. (Photo by Peter Nicholls/Reuters)

The towers of Russky Bridge are seen over the fog covered Vladivostok, Russia on May 26, 2020. The so-called “fog season” on the Pacific coast and in the south of Russia's Primorye Territory lasts from April till September. (Photo by Yuri Smityuk/TASS)

A girl picks catkins at a field amid the COVID-19 pandemic in Sarighat, on the outskirts of Dhaka, Bangladesh, October 2, 2020. (Photo by Mohammad Ponir Hossain/Reuters)

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 police officer speaks to a driver shortly after midnight in Bucharest, Romania, Monday, November 9, 2020 informing him of the pandemic related night traffic restrictions that just came into effect. Romania introduces new restrictions aimed at limiting the spread of the COVID-19 infections following a week when it registered an all time high number of new infections. (Photo by Vadim Ghirda/AP Photo)

A child working at Ship breaking yard in Chittagong, Bangladesh on November 14, 2014. (Photo by Pascal Mannaerts/Alamy Stock Photo)

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)