Photo taken with a mobile phone shows a scenery after rain at Guangyanggu City Forest Park in Xicheng District of Beijing, capital of China, on July 10, 2019. (Xinhua/Ding Jing)

Photo taken with a mobile phone shows a snail after rain at Guangyanggu City Forest Park in Xicheng District of Beijing, capital of China, on July 10, 2019. (Xinhua/Ding Jing)

Photo taken with a mobile phone shows a scenery after rain at Guangyanggu City Forest Park in Xicheng District of Beijing, capital of China, on July 10, 2019. (Xinhua/Ding Jing)

Photo taken with a mobile phone shows a flower after rain at Guangyanggu City Forest Park in Xicheng District of Beijing, capital of China, on July 10, 2019. (Xinhua/Ding Jing)

Photo taken with a mobile phone shows a scenery after rain at Guangyanggu City Forest Park in Xicheng District of Beijing, capital of China, on July 10, 2019. (Xinhua/Ding Jing)

Photo taken with a mobile phone shows a man doing exercises in Beijing, capital of China, on July 5, 2019. (Xinhua/Zhang Chuanqi)