The industrial smog typically exists in the urban industrial areas where the large scale burning of the fossil fuels may lead to generation of huge amount of smoke and sulfur dioxide gas liberated into the atmosphere. These gaseous products gets mixed with the droplets of fog already present in the atmosphere. This lead to the formation of industrial smog. The industrial smog forms a thick blanket of smog or haze nearly close to the ground.
The correct answer is industrial smog. This type of smog exists in coal power plants which creates smoke and sulfur dioxide which may mix with fog creating a thick blanket of haze. Sulfur dioxide is one primary component of an industrial smog.
