Story highlights Choking smog leads to dire warnings

Air quality at dangerous levels

(CNN) First it was Beijing. Then Delhi. Now it's Tehran.

Hundreds of deaths are being blamed on the thick, hazy smog that has choked Iran's capital this month, as Iranian officials scramble for solutions to the city's ever-growing pollution crisis.

It's so severe that Iran's Supreme Leader has even weighed in, calling on Iranians to stop driving their personal vehicles during days when pollution levels are high.

Smog isn't unusual in Tehran, particularly at this time of the year. The city is surrounded by mountains and suffers from chronic traffic jams, with low rainfall and a lack of strong wind streams. As a result, the city's landscape acts as a sort of funnel, with heavy emissions from millions of vehicles unable to escape the city.

The result is a choking, thick haze that blankets the city, often obscuring the city's prominent landmarks. Although Tehran's air pollution is common, this week, Iranian officials have issued a series of dire warnings, suggesting the crisis is far worse than any the city has previously faced.

An Iranian woman wears mask as she walk in a street in Tehran on November 16, 2016.

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