The air pollution in Tehran, with over 12 million population, is more than three times the level considered safe.

The committee also extended restrictions on the movement of cars in Tehran, and people were advised not to participate in group exercises in parks and green spaces.

The pollution is expected to stay longer above Tehran unless rare winds and rains to move the stagnant air.

Other major cities including Tabriz, Qom, Arak, Isfahan and Karaj also experienced poor air quality this week that reached its critical level on Tuesday.

Schools in Tabriz and Karaj were also closed due to poor air quality.

In the past years, Iran's government and parliament made several efforts to solve Tehran's air pollution, including imposing restrictions on the city's traffic flow, passing measures urging safer fuel and replacing old, inefficient cars with new ones.