Chinese artist Kong Ning poses in a costume symbolizing a butterfly, which is decorated with 365 masks on its wings to represent the number of days in a year, during her performance art at the Badaling section of the Great Wall on the outskirts of Beijing January 1, 2015. Kong, whose works include themes related to China's air pollution problem, named her new performance art “Hua Die” (transforming into a butterfly) and performed it on the first day of the new year as she hopes that China has clean air for this year. (Photo by Kim Kyung-Hoon/Reuters)

A woman wearing a mask reacts at her garden which locates next to chimneys of coal-fired power plant in Shijiazhuang, Hebei province, China, January 28, 2015. Beijing introduced tougher regulations this year to combat pollution, keen to overhaul China's unwanted image of smog-choked cities, fouled waterways and heavy-metal tainted soil. (Photo by Kim Kyung-Hoon/Reuters)

Participants hang from ropes as they learn how to use safety gears at an experience centre for construction safety training in Beijing, September 5, 2014. The centre which opened in June 2014 was established to educate workers about construction safety. According to the centre, about 1,000 construction workers undergo 3-hour classes which comprises of 33 modules every month. (Photo by Kim Kyung-Hoon/Reuters)

A man wearing a face mask to help protect from the coronavirus carries a bag of groceries as he walks by a mural depicting an iconic financial market bull statue near the central business district, Monday, April 18, 2022, in Beijing. (Photo by Andy Wong/AP Photo)

A train attendant wearing a protective face mask stands on a train to Wuhan, at the railway station in Beijing, China, 29 March 2020. Wuhan, the epicenter of the coronavirus outbreak, partly lifted the lockdown allowing people to enter the city after more than two months. Chinese authorities eased the quarantine measures as cases of Covid-19 across China have plummeted, according to Chinese government figures. (Photo by Roman Pilipey/EPA/EFE)

People dance during a heavy metal concert at Omni Space in Beijing, China, August 14, 2020. China boasts a small but buoyant heavy metal scene, where bands mix genre standards with Chinese elements. Black metal is a sub-genre that creates a dark, moody atmosphere layering heavily distorted guitars and high-pitched vocals. (Photo by Thomas Peter/Reuters)

Monks dressed as Tibetan Buddhism characters attend a religious ceremony, known as “Da Gui” or beating ghost, to celebrate the upcoming Tibetan New Year which starts on March 1 at Yonghegong Lama Temple, in Beijing February 28, 2014. This Tibetan ceremony is held annually at the end of the first lunar month with mask dancing to expel ghosts, according to a press release. (Photo by Jason Lee/Reuters)

A mechanical horse-dragon made of wood and steel is presented to the public in Nantes, western France on August 26, 2014. This horse-dragon, created by the French artist Francois Delaroziere of “Les Machines de l'île” (The Machines of the Isle), is the hero of the show "Long Ma" which will be presented in Beijing on October 17, 2014 as part of the fiftieth anniversary of the relationship between France and China. (Photo by Jean-Sebastien Evrard/AFP Photo)