Why is it foggy in Nanchang recently?

According to meteorologists, generally speaking, in the lower atmosphere, the temperature decreases with the increase of altitude, but sometimes it increases with the increase of altitude. This phenomenon is called inversion, and the atmosphere with inversion is called inversion layer In the "inversion layer", warmer and lighter air is located above colder and heavier air, just like a "pot cover" covering the city, which seriously hinders the convection movement of air. The appearance of "inversion layer" makes water vapor, smoke dust and various harmful gases in the air float in the atmosphere near the ground, thus forming haze weather.