Tehran Air Cleaner in Sept.

Air quality monitoring stations in the capital city of Tehran showed that its residents were breathing fresh air in September compared to the year-ago month.
According to charts regularly published by Tehran Air Quality Control Company, during the month, moderate air quality status dominated the whole period.
In other words, the Air Pollution Index hovered between 51 and 100 throughout the month.
The index categorizes conditions dictated by a measure of polluting matters into good (0-50), moderate (51-100), unhealthy for sensitive groups (101-150), unhealthy (151-200), very unhealthy (201-300) and hazardous (301-500).
The fluctuating AQI reached its highest level (97) on Sept. 9-10.
TAQCC comparative data show that September 2019 ended with a worsening of air quality. The company recorded 27 moderate days in the month and the remaining three days kept the vulnerable people inside their house, as AQI entered the range of 101 to 150, which translates into unhealthy status for the group.
A broader view, however, reveals that the city’s air quality in the first half of the current Iranian year (March 20-Sept. 21) had worsened compared to the same period of last year.
Citizens experienced 15 good air days and 133 days with moderate air quality. The health-wise vulnerable people were warned to limit their outdoor activities in 36 days, as the index hit the unhealthy status for the sensitive group.
AQI hit the emergency level, hitting the unhealthy status for all in the two remaining days.