Photo taken on Sept. 27, 2020 shows workers planting trees for the 2022 Beijing Winter Olympics in Yanqing District, Beijing, capital of China. (Xinhua/Zhang Chenlin)

Photo taken on Sept. 27, 2020 shows workers lay eco-bags loaded with soil and seeds on a slope for the 2022 Beijing Winter Olympics in Yanqing District, Beijing, capital of China. (Xinhua/Zhang Chenlin)

Photo taken on Sept. 27, 2020 shows the autumn scenery of Yanqing District, Beijing, capital of China. (Xinhua/Zhang Chenlin)

Photo taken on Sept. 27, 2020 shows a worker preparing to defrost the track of the National Sliding Center in Yanqing Zone for the 2022 Beijing Winter Olympics, Beijing, capital of China. Construction of the National Sliding Center in Yanqing of Beijing has seen big progress that it began ice-making on Sept. 18 and is estimated to finish at the end of the month before China's national team train in the National Sliding Center in early October. (Xinhua/Zhang Chenlin)

Photo taken on Sept. 27, 2020 shows workers defrosting the track in the National Sliding Center in Yanqing Zone for the 2022 Beijing Winter Olympics, Beijing, capital of China. Construction of the National Sliding Center in Yanqing of Beijing has seen big progress that it began ice-making on Sept. 18 and is estimated to finish at the end of the month before China's national team train in the National Sliding Center in early October. (Xinhua/Zhang Chenlin)

Photo taken on Sept. 27, 2020 shows workers defrosting the track in the National Sliding Center in Yanqing Zone for the 2022 Beijing Winter Olympics, Beijing, capital of China. Construction of the National Sliding Center in Yanqing of Beijing has seen big progress that it began ice-making on Sept. 18 and is estimated to finish at the end of the month before China's national team train in the National Sliding Center in early October. (Xinhua/Zhang Chenlin)

Photo taken on Sept. 27, 2020 shows an external view of the National Sliding Center in Yanqing Zone for the 2022 Beijing Winter Olympics, Beijing, capital of China. Construction of the National Sliding Center in Yanqing of Beijing has seen big progress that it began ice-making on Sept. 18 and is estimated to finish at the end of the month before China's national team train in the National Sliding Center in early October. (Xinhua/Zhang Chenlin)

Photo taken on Sept. 27, 2020 shows workers defrosting the track in the National Sliding Center in Yanqing Zone for the 2022 Beijing Winter Olympics, Beijing, capital of China. Construction of the National Sliding Center in Yanqing of Beijing has seen big progress that it began ice-making on Sept. 18 and is estimated to finish at the end of the month before China's national team train in the National Sliding Center in early October. (Xinhua/Zhang Chenlin)

Photo taken on Sept. 27, 2020 shows workers defrosting the track in the National Sliding Center in Yanqing Zone for the 2022 Beijing Winter Olympics, Beijing, capital of China. Construction of the National Sliding Center in Yanqing of Beijing has seen big progress that it began ice-making on Sept. 18 and is estimated to finish at the end of the month before China's national team train in the National Sliding Center in early October. (Xinhua/Zhang Chenlin)

Photo taken on Sept. 27, 2020 shows the track of the National Sliding Center in Yanqing Zone for the 2022 Beijing Winter Olympics, Beijing, capital of China. Construction of the National Sliding Center in Yanqing of Beijing has seen big progress that it began ice-making on Sept. 18 and is estimated to finish at the end of the month before China's national team train in the National Sliding Center in early October. (Xinhua/Zhang Chenlin)

Photo taken on Sept. 27, 2020 shows a worker piling up eco-bags loaded with soil and seeds for the 2022 Beijing Winter Olympics in Yanqing District, Beijing, capital of China. (Xinhua/Zhang Chenlin)

Photo taken on Sept. 27, 2020 shows workers planting trees for the 2022 Beijing Winter Olympics in Yanqing District, Beijing, capital of China. (Xinhua/Zhang Chenlin)

Photo taken on Sept. 27, 2020 shows a suveyer checking the vegetation growth for the 2022 Beijing Winter Olympics in Yanqing District, Beijing, capital of China. (Xinhua/Zhang Chenlin)