Migrant workers hang on to a door of a moving bus as they return to their villages after Delhi government ordered a six-day lockdown to limit the spread of the coronavirus disease (COVID-19), in Ghaziabad on the outskirts of New Delhi, India, April 20, 2021. (Photo by Adnan Abidi/Reuters)

People stand next to a ship, containing tonnes of hazardous mercury-mixed oil, as it was allowed to anchor at Gadani ship-breaking yard in Gadani, Pakistan, 28 May 2021. Authorities have launched an investigation into the anchoring of a ship at the Gadani shipbreaking yard despite Interpol's warning that the ship contains dangerous chemicals. (Photo by Rehan Khan/EPA/EFE)

A racegoer reacts to picking a winner in the first race on the third day of the Royal Ascot horserace meeting, which is traditionally known as Ladies Day, at Ascot, England Thursday, June 17, 2021. (Photo by Alastair Grant/AP Photo)

Katie Rose Hobbs and Kirsten Elizabeth Pobjoy of British Aerosuperbatics Wingwalking Team perform ballet in the air during Huangguoshu Waterfalls Flight Conference on August 3, 2018 in Anshun, Guizhou Province of China. Huangguoshu Waterfalls Flight Conference including 18 aircraft from seven aerobatic teams from all over the world kicked off on Friday. (Photo by VCG via Getty Images)

An alarmed squirrel. (Photo by Mary McGowan/Barcroft Images/Comedy Wildlife Photography Awards)

A South Korean marine in action during their regular drill on Yeonpyeong Island, South Korea November 1, 2018. (Photo by Jeon Heon-Kyun/Pool via Reuters)

A Beijing Opera performer dances for a show by designer Hao Weimin at China Fashion Week, China, October 28, 2019. (Photo by Jason Lee/Reuters)

People and Nature category winner: Why did the sloth cross the road? by Andrew Whitworth (Osa Conservation and University of Glasgow), taken in Osa Peninsula, Costa Rica. “I was driving out from the Osa Peninsula, located on the southern Pacific coast of Costa Rica on a dark, stormy day. This female three-toed sloth (Bradypus variegatus) had luckily just about made it across the road, and the drivers of the Toyota on this occasion had spotted her in good time”. (Photo by Andrew Whitworth/2019 British Ecological Society Photography Competition)