Tehran 23rd Most Polluted Capital

Based on the average yearly PM2.5 concentration, Tehran is ranked as the 23rd most polluted capital in the world by the Swiss-based air quality monitoring company IQAir AirVisual.
IQAir AirVisual is a nonprofit firm trying to promote access to real-time air quality information, aggregate and validate real-time data from governments and monitors operated by individuals and organizations across continents.
According to the firm’s 2018 World Air Quality Report published on airvisual.com, the sprawling Iranian capital is ranked as the 23rd most polluted capital based on the average yearly PM2.5 concentration.