A woman wearing a mask walk in a street in a Yonghegong Lama temple compound seen shrouded in smog in Beijing, China, 30 November 2015. Beijing issued an orange alert for heavy smog 30 November, the highest level this year. Authorities in the Chinese capital warned of 'severe pollution' and advised the capital's 20 million inhabitants to stay indoors. (Photo by How Hwee Young/EPA)

Russian President Vladimir Putin, right, and North Korea's leader Kim Jong Un pose for photographers during their meeting in Vladivostok, Russia, Thursday, April 25, 2019. Putin and Kim are set to have one-on-one meeting at the Far Eastern State University on the Russky Island across a bridge from Vladivostok. The meeting will be followed by broader talks involving officials from both sides. (Photo by Alexander Zemlianichenko/AP Photo/Pool)

Protesters wear gas masks in the front of the Romanian Environment Ministry in Bucharest March 4, 2019, to demand better air. Dozens of people holding placards reading “Our children don't breath air anymore” gather in the front of the Environment Ministry to ask for better breathable air in Bucharest. (Photo by Daniel Mihailescu/AFP Photo)

Some bats in the forested area of Guapiles, Costa Rica, 21 April 2020. (Photo by Jeffrey Arguedas/EPA/EFE)

A woman is arrested during a mass gathering protest organised by the group called “UK Freedom Movement”, in Hyde Park in London as the country is in lockdown to help stop the spread of coronavirus, Saturday, May 16, 2020. The group claims that the coronavirus lockdown is illegal. (Photo by Kirsty Wigglesworth/AP Photo)

Grave diggers wearing personal protective equipment (PPE) walk away after burying a person, who presumably died of the coronavirus disease (COVID-19), in the special purpose section of a graveyard on the outskirts of Saint Petersburg, Russia on May 13, 2020. (Photo by Anton Vaganov/Reuters)

Coronavirus infection (COVID-19) is still continuing in the country, a guard of Gyeongbokgung Palace wears a protective mask with a goblin pattern at the entrance of the palace, which is currently not being opened to the public due to Covid-19 in Seoul, South Korea on June 18, 2020. (Photo by Chris Jung/NurPhoto via Getty Images)

A woman takes a selfie picture at the Poklonnaya Hill in western Moscow near the main building of the Moscow State University on June 17, 2020, as the air temperature approaches 30 degrees Celsius. (Photo by Alexander Nemenov/AFP Photo)