A man wearing a mask and dressed in a clown costume rides an electric tricycle while carrying a container in the shape of a rubber duck amid heavy smog in Beijing, China, December 29, 2015. (Photo by Jason Lee/Reuters)

Tourists kissing front of Malaysia's landmark Petronas Twin Towers with lights on before turned off to mark Earth Hour 2016 in Kuala Lumpur, Malaysia, 19 March 2016. Earth Hour takes place worldwide at 8.30 p.m. local time and is a global call to turn off lights for 60 minutes to raise awareness of the danger of global climatic change (Photo by Fazry Ismail/EPA)

A “jungle nymph” is measured during the annual weight-in ZSL London Zoo on August 21, 2014 in London, England. The height and mass of every animal in the zoo, of which there are over 16,000, is recorded and submitted to the Zoological Information Management System. This is combined with animal measurement data collected from over 800 zoos and aquariums in almost 80 countries, from which zoologists can compare information on thousands of endangered species. (Photo by Oli Scarff/Getty Images)

Singer Rihanna prepares for a photoshoot with photographer Annie Leibovitz in Havana, Cuba, May 28, 2015. (Photo by Reuters/Stringer)

In this photo taken on Thursday, July 23, 2015 migrants enter a train to Serbia at the railway station in the southern Macedonian town of Gevgelija. The country has become a major transit route for thousands of Middle Eastern and African refugees and migrants who cross over from Greece and then continue into Serbia. (Photo by Boris Grdanoski/AP Photo)

An Iranian girl walks past a mural with Iran's national flag in a street in Tehran, Iran, 03 December 2020. Iranian president Rouhani said that his government does not agree with the parliament's draft bill to quit the nuclear deal, to reduce nuclear commitment and to increase nuclear activities. The development comes after the assassination of Iranian nuclear scientist Mohsen Fakhrizadeh earlier this week. (Photo by Abedin Taherkenareh/EPA/EFE/Rex Features/Shutterstock)

A man walks inside the flooded Cochin international airport after the opening of Idamalayar, Cheruthoni and Mullaperiyar dam shutters following heavy rain, on the outskirts of Kochi, India, August 15, 2018. (Photo by Sivaram V/Reuters)

People dance in a park on a foggy day in Huai'an, Jiangsu province, China October 10, 2017. (Photo by Reuters/China Stringer Network)