Tehran, Nov 30 (IANS): Heavy air pollution has forced the Iranian authorities to close schools and universities in a number of cities including Tehran, official IRNA news agency reported.

Tehran's Deputy Governor on Friday announced that all kindergartens, schools as well as universities would be closed on Saturday, Xinhua reported, citing IRNA.

Tehran province's Air Pollution Exigency Committee imposed restrictions on the movement of cars, and people were advised not to participate in group activity in parks and green spaces.

The air pollution in Tehran, with over 12 million population, has reached the level considered unsafe for all groups of people.

Thick smog is hanging over the Iranian capital city. Heavy traffic, factory pollution and lack of wind and rain in recent days have worsened the air quality.

Other cities including Karaj, Isfahan and Urmieh also experienced poor air quality and the officials of those cities also announced schools would be closed on Saturday, according to the report.

Iran's government and Parliament have made several efforts to reduce Tehran's air pollution over the past years, such as imposing restrictions on the city's traffic flow, passing measures urging safer fuel and replacing old, inefficient cars with new ones.