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 watch as lava flows from an eruption of a volcano on the Reykjanes Peninsula in southwestern Iceland late on Monday, March 29, 2021. Iceland's latest volcano eruption is still attracting crowds of people hoping to get close to the gentle lava flows. The eruption in Geldingadalur, near Iceland's capital Reykjavik, is not seen as a threat to nearby towns and the slow flows mean people can get close to action without too much harm. (Photo by Marco Di Marco/AP Photo)

This photo taken on April 4, 2021 shows migratory birds flying over a wetland near the Yalu River in Dandong, in China's northeastern Liaoning province. (Photo by AFP Photo/China Stringer Network)

A calico sits in its enclosure and suns itself in Hessen, Germany on May 28, 2021. The Opel Zoo presents a walk-in Madagascar aviary for caltas and varis. The primate species is native to Madagascar and is threatened with extinction. (Photo by Andreas Arnold/dpa)

Moichara or Bull race is a rural festival where a pair of bulls race each other during the monsoon season. This race is performed by a farmer in Parganas, India on July 4, 2021. (Photo by Sumit Sanyal/SOPA Images/Rex Features/Shutterstock)

A laborer is transporting used oil durms by a hand-pulled vehicle near Buriganga River in Dhaka on June 12, 2021. (Photo by Md Rakibul Hasan/ZUMA Wire/Rex Features/Shutterstock)

Creative imagery, gold winner: Sprats and Bread, Ruediger Schulz, Germany. (Photo by Ruediger Schulz/2021 Bird Photographer of the Year)

A Bengal tigress who gave birth to four cubs at the Guadalajara Zoo, Jalisco state, Mexico runs at the zoo on October 5, 2021. (Photo by Ulises Ruiz/AFP Photo)