Why can't you see the sun in winter in Wulong District of Chongqing?

Because of the smog in Wulong District of Chongqing, the sun has not been seen in winter. According to relevant public information, Chongqing is located in the Erjiang area, with high air humidity and prone to fog. Therefore, Chongqing is also known as the foggy city. It is rainy all the year round in winter, especially in the Yangtze River and Jialing River. The water vapor condenses into smog and the sun is invisible. On the contrary, summer is mostly hot and it is a heavy industry base, and exhaust emission is also one of the reasons, which leads to poor air quality index.