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 fireworks commemorating the 76th anniversary of the victory in the Great Patriotic War in St. Petersburg, Russia, May 9, 2021. (Photo by Chine Nouvelle/SIPA Press/Rex Features/Shutterstock)

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 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)

A caiman in the Pantanal region of Brazil in 2021. They are used to seeing humans, allowing the photographer, Leighton Lum, a close-up shot. (Photo by Leighton Lum/Caters News Agency)

A hiker admires the view as Mt. Etna, Europe's largest active volcano, erupts in the background, in the Bove Valley of Etna Park, on the eastern slope of Mt. Etna, in Sicily, southern Italy, Sunday, July 4, 2021. Since Feb. 16, 2021, Mt. Etna has begun a series of eruptive episodes. (Photo by Salvatore Allegra/AP Photo)

A Taliban fighter poses for a picture holding a flower before offering Friday noon prayers in Kabul, Afghanistan on October 1, 2021. (Photo by Bulent Kilic/AFP Photo)

A member of Korean Federation for Environmental Movement in a Santa Claus outfit attaches dumped cigarette butts at a cigarette butt Christmas tree in front of Korea Tobacco & Ginseng Corporation office in Seoul, South Korea, Monday, December 23, 2019. The environmental activist group called for a ban on the use of plastic for cigarette filters as part of efforts to protect the environment from toxic plastic pollution. (Photo by Ahn Young-joon/AP Photo)