The Iranian capital city’s air quality index was at 145 in the late hours of Sunday.
Tehran has had 195 days with acceptable air quality and 64 days with air quality unhealthy for sensitive groups as well as 6 days rated unhealthy for all since the beginning of the new Iranian calendar year, which began on March 21.
High pollution rate during the cold seasons have turned into a major problem in large Iranian cities over the past years.
Officials say fossil fuels used by millions of vehicles, power plants and factories are the main culprits for the air pollution.
