Photo taken with a mobile phone shows the sunset at Beijing Wild Duck Lake National Wetland Park in Beijing, capital of China, March 17, 2019. [Photo/Xinhua]

Photo taken with a mobile phone shows the spring scenery at Beijing Wild Duck Lake National Wetland Park in Beijing, capital of China, March 17, 2019. [Photo/Xinhua]

Photo taken with a mobile phone shows blossoming flowers in Beijing, capital of China, March 22, 2019. [Photo/Xinhua]

Photo taken with a mobile phone shows tourists visiting the Summer Palace in Beijing, capital of China, March 16, 2019. [Photo/Xinhua]