What do you mean the weather forecast is mild?

Light pollution refers to light haze or moderate fog, that is, Pm2.5 is less than 100. Fog, like clouds, has obvious boundary with clear sky area, and the droplet concentration distribution is uneven. The droplet size is large, ranging from a few microns to 100 micron, with an average diameter of about 10-20 micron. The naked eye can see the droplets floating in the air. Because the light scattered by fog composed of liquid water or ice crystals has little to do with wavelength, the fog looks milky white or bluish white. With the deterioration of air quality, cloudy days are increasing and the harm is increasing.