Visibility lessener is a term used to describe any type of atmospheric phenomenon that reduces visibility. The three most common examples are MIST, HAZE, and FOG. MIST is a collection of tiny water droplets suspended in the air, while HAZE is a dry suspension of dust or smoke particles in the air. FOG is a thick cloud of tiny water droplets that is near the ground. All three of these phenomena reduce visibility by blocking out light from the sun.