A smokestack is a large chimney or exhaust pipe used for emitting fumes, gases, and smoke from industrial processes. It typically stands tall on top of factories, power plants, and other industrial facilities where there is a need to expel pollutants into the atmosphere. Smokestacks are often associated with older forms of energy production such as coal-fired power plants or steel mills that produced large amounts of smoke and soot. In modern times, smokestacks have evolved to include scrubbers and other technologies designed to reduce emissions and improve air quality.