Air pollution closes schools in Tehran

Tehran's primary and high schools were closed on Tuesday because of dangerously polluted air.All outdoor sport activities were also banned in the capital which has over 10 million residents.

The air pollution index stood at 159, indicating it was unhealthy for everyone.Tehran’s air is among the most polluted in the world and school closures because of poor air quality are a regular occurrence.The smog is mostly caused by heavy traffic as well as factory pollution and typically worsens during the cold season.

In July, schools and government offices closed in Tehran and several other cities in the country after a sandstorm blanketed the Iranian capital and the surrounding region.