It is impossible to see through fog because:

Because of scattering, we can't see through the fog. Light will be scattered by atoms and molecules in the air, as well as anything carried in the air like dust or smoke. Water droplets, which are present in fog, scatter light as well. The light that falls on an object and is reflected a viewer can be scattered all the way to hell and back before it reaches the point where it can be seen by an observer.