Tehran is the capital city of Iran. It has some 8.7 million inhabitants, making it one of the most populous cities in Iran as well as the whole of west Asia. The levels of pollution in Tehran are a topic of great importance for its citizens, with large quantities of smoke and dust filling Tehran each year, so much so to the point that the country is considering moving the capital to another location (with other attributable factors such as earthquakes also playing a part in this decision, which has yet to see any progress since its announcement in 2010).

There are a number of reasons for Tehran's pollution levels, with some lying in the industrial sector, vehicular sector as well as its geography, with the sizeable Alborz mountain range to the north of the city contributing to its pollution readings, due to allowing smoke and dust to accumulate and not disperse properly due to lack of wind being trapped in a ‘pollution sink’.