Air pollution is the contamination (աղտոտում) of the natural air by mixing it with different pollutants such as harmful fumes (ծուխ) and chemicals.
Water pollution is the contamination of the water on Earth. It includes contamination by pollutants such as chemical, bacterial or particulate (մասնիկներ) that reduces the purity of the water.
Noise pollution is the loud noise that is created by human activity that disrupts (վնասել) the standard of living in the affected area. Pollution can stem from things such as traffic, railroads, concerts, loud music, airplanes, fireworks etc.
Light pollution is the over illumination of a certain area that is considered as obtrusive. It is considered pollution especially when it interferes with astronomical observation. The most common way to determine if an area is polluted is to look at the stars, if you can see them, your area is not so polluted.