Clearer air after snowfall in Tehran

Locals in Tehran enjoyed some clean air after weeks of severe air pollution, thanks to a heavy snowfall on Wednesday.

The Iranian capital, home to over 10 million residents, is among the most polluted cities in the world, and schools often close because of poor air quality.

The pollution is mostly caused by heavy traffic as well as pollution from factories that typically worsens during the cold season.In recent weeks schools were repeatedly closed because of severe pollution and smog.As cold, stagnant air settles in the valley, it traps car and other emissions that have no way of escaping.