This picture taken on May 31, 2018 shows a villager walking between abandoned houses covered with overgrown vegetation in Houtouwan on Shengshan island, China' s eastern Zhejiang province. Houtouwan was a thriving fishing community of sturdy brick homes that climb up the steeply hilled island of Shenghshan, but is now abandoned, with entire houses completely overgrown as if vacuum- sealed in a lush layer of green. (Photo by Johannes Eisele/AFP Photo)

A man cuts dog meat at a dog meat restaurant ahead of local dog meat festival in Yulin, Guangxi Zhuang Autonomous Region, China on June 21, 2018. The festival in the southwestern town of Yulin has long drawn international criticism, with thousands of dogs traditionally being killed during the event. (Photo by Tyrone Siu/Reuters)

A woman dressed in a Tang-dynasty costume performs at a show by designer Chu Yan at China Fashion Week in Beijing, China, October 30, 2018. (Photo by Jason Lee/Reuters)

This aerial picture taken on the night of November 12, 2018 shows traffic on an elevated intersection in downtown Shanghai, China. (Photo by Johannes Eisele/AFP Photo)

A boy rides on a snow wagon towed by a robot dressed as a Teddy bear, which only moves forward by moving its legs, during the Ice and snow carnival at Taoranting park in Beijing February 9, 2015. (Photo by Kim Kyung-Hoon/Reuters)

People pass a suitcase as they line up to enter a railway station in Beijing, February 15, 2015. Chinese Ministry of Transport said a total of 2.807 billion trips are expected to be made during the 40-day Spring Festival travel rush, which started on February 4 and will last until March 16, Xinhua News Agency reported. (Photo by Reuters/Stringer)

A migrant carries his belongings as he arrives at the Beijing railway station to catch a train in Beijing, Friday, February 13, 2015. (Photo by Andy Wong/AP Photo)

File photo taken on July 24, 2011 shows the scenery of karst landform in Dacai Township under Maonan Autonomous County of Huaijiang, south China's Guangxi Zhuang Autonomous Region. The World Heritage Committee on Monday inscribed an extension of South China Karst, a natural World Heritage Site since 2007, into the UNESCO's World Heritage List. (Photo by Wang Xiufa/Xinhua)