TEHRAN — Tehran enjoyed the cleanest air of the past five years in the first half of the current Iranian calendar year (March 20-September 21, 2016), Tehran Air Quality Control Company spokeswoman Leila Nazari said.

Comparing the air quality indices of the past five and a half years indicate that the capital’s air quality was at its best over the past six months, Khabaronline quoted Nazari as saying.

Out of 186 days of spring and summer the air quality in Tehran was at a standard level for 163 days, Nazari said, noting, 23 days were reported as lightly polluted with possibility of causing discomfort for individuals with heart and lung condition.

11 days were of excellent air quality, 152 days of good air quality and no single day of heavy air pollution was reported in the same period, she added.

Of the first 186 days of spring and summer of 2011 only 68 days of good air quality and no single day of excellent air quality were reported and the number increased to 126 days in 2012.

In 2013 only two days of excellent air quality and 128 days of good air quality were reported over the same period and the number grow to 7 days of excellent air quality and 138 days of good air quality in 2014.

And finally in 2015, 10 days of excellent air quality and 135 days of good air quality were announced.

MQ/MG