According to the company, the air quality was at 97, which is acceptable, during the past 24 hours.
Tehran has had 11 days of unhealthy air quality for sensitive groups since the turn of the year on March 21, as well as two days in which air quality entered the dangerous zone. This is hugely worst than the previous year in the same period.
Amid the pollution, the deputy governor of Tehran Province declared all schools, universities and government departments closed on Tuesday.
He said the air quality is expected to worsen during the day.
