Air pollution in the capital Dec 29, 2020 The air quality of the capital, in terms of the concentration of particulate matter pollution is less than 2.5 microns with an instantaneous index of 165 in unhealthy conditions for all groups in society today, December 30, 2020. Since the beginning of this year, 15 days of clean air, 181 days of acceptable or healthy air, 87 days of unhealthy weather for sensitive groups and 5 days of unhealthy weather for all groups have been recorded in Tehran. Shayan Mehrabi https://www.tehranpicture.ir/u/8He