Financial Tribune - Charts regularly published by Tehran Air Quality Control Company show that all through October, Air Quality Index hovered between 51 and 100, showing the dominance of "moderate" status

Tehran’s residents experienced a more stable air condition during October after being exposed to hazardous emissions in early fall, mostly due to traffic congestion coinciding with the opening of schools in late September.

Charts regularly published by Tehran Air Quality Control Company show that all through October, Air Quality Index hovered between 51 and 100, showing the predominance of "moderate" status.

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).

In the last three days of September, AQI crossed 101 and entered the threshold of "unhealthy" conditions for sensitive groups.

Children, the elderly, pregnant women and those with respiratory and cardiovascular conditions fall in the above group.