Vehicles pass through the heavy fog and air pollution that cover Skopje valley in the early morning, in Skopje, The Former Yugoslav Republic of Macedonia, 14 December 2017. According to media reports, Skopje is considered one of the most polluted cities in the world. (Photo by Georgi Licovski/EPA/EFE)

A migrant worker wearing face masks to help curb the spread of the coronavirus walks up to a pedestrian bridge in Beijing, Sunday, December 6, 2020. Provincial governments across China are placing orders for experimental, domestically made coronavirus vaccines, though health officials have yet to say how well they work or how they may reach the country's 1.4 billion people. (Photo by Andy Wong/AP Photo)

A woman in a wedding dress walks on the dried-up riverbed of the Jialing river, a tributary of the Yangtze, that is approaching record-low water levels in Chongqing, China on August 18, 2022. (Photo by Thomas Peter/Reuters)

“Mount Hua, or Hua Shan, or Xiyue located near the city of Huayin in Shaanxi province, about 120 kilometres (75 mi) east of Xi'an. It is one of China's Five Great Mountains, and has a long history of religious significance. Originally classified as having three peaks, in modern times the mountain is classified as five main peaks, of which the highest is the South Peak at 2,154.9 metres (7,070 ft)”. – Wikipedia

Photo: Trip to Xi'an 西安. (Photo by Grant Robinson)

The buildings of the banking district are seen through thousands of rain drops on a glass railing in central Frankfurt, Germany, Wednesday, January 11, 2017. (Photo by Michael Probst/AP Photo)

A cat sits underneath lanterns displayed at Tai O fishing village on September 07, 2022 in Hong Kong, China. Hong Kong prepares ahead to celebrate the mid-autumn festival which is an occasion for a children's night out and family gathering with the customs of moon contemplating, a procession of star and moon-shaped lanterns, lion dance, as well as holding parties with moon cakes and fruits. (Photo by Anthony Kwan/Getty Images)

A tourist takes photos among fireweed, or kochia scoparia, at an archaeological site park on September 13, 2022 in Xi'an, Shaanxi Province of China. (Photo by Zhang Yuan/China News Service via Getty Images)

This photo taken on December 2, 2023 shows pandas eating inside their enclosure at a zoo in China's southwestern Chongqing municipality. (Photo by AFP Photo/China Stringer Network)