TEHRAN — Since the beginning of the current year on March 21 citizens of the capital have breathed 17 days of excellent air quality, IRNA news agency reported on Tuesday.

An air quality index (AQI) is used by government agencies to communicate to the public how polluted the air currently is or how polluted it is forecast to become.

The index categorizes conditions according to a measure of polluting matters into excellent (0-50), good (51-100), lightly polluted or unhealthy for sensitive groups (101-150), moderately polluted (151-200), heavily polluted (201-300) and severely polluted (301-500).

The report highlights that in the same period last year only 2 days of excellent air quality was reported.

Moreover, the first 20 days of the year 1397 (March 2018- March 2019) 5 days of unhealthy air quality for sensitive groups were reported as well.

Heavy rainfalls is the major reason behind improved air quality in the metropolis of Tehran.

Director of National Drought Warning and Monitoring Center (NDWMC) Sadeq Ziaeian told the Tehran Times on Friday that since the beginning of the current water year (starting on September 23, 2018) the whole country has received 256 millimeters of precipitation on average and this is while the average precipitation the country received in the long-term amounts to 232 milliliters.

NDWMC director went on to say that the amounts indicate a 39-percent increase compared to long-term averages and a 184-percent rise compared to the same period last year.

MQ/MG