Why did I often see foggy weather when I was a child, but now it is rare?

Because when I was a child, there was little air pollution and the air was humid, which was easy to form fog. Now the air is dry and the pollution is very serious. Now I am troubled by smog. It's hard to write my day now. It's foggy now. Now the pollution is serious and the air is dry, so it is difficult to form fog. Because the process of urbanization is accelerating, the concept of environmental protection is constantly strengthening. There are fewer and fewer conditions to form fog, so it is rare to see foggy weather now.