Tehran Air Quality Slightly Better in February

In February Tehranis had some relief with better air quality compared to the month last year, data from Tehran Air Quality Control Company shows. 
Charts published on TAQCC website, airnow.tehran.ir show that in February, the capital breathed less polluted air. 
Bright blue skies were seen for almost one-fourth of the investigated period, as the air quality index was in 'good' condition for seven days. 
The index compartmentalizes conditions according to 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).