The exhaust, lead, and asbestos emitted by these sorry vehicles are trapped by the two nearby mountain ranges, which meet to the northeast of the city. Weak winds and temperature inversions force the fumes and particulates to form a blanket of brown smog over the city. The pollution lessens as one ascends the mountain, hence the desirability of north Tehran addresses, but the air is not really good anywhere in Tehran. Anyone with cardiac or pulmonary disease should stay away. The city water is marginally potable.
Most newcomers get a mild bout of diarrhea.
Notwithstanding the strong Islamic moral code, current unemployment and poverty has caused an increase in theft. Car radios and cell phones are common targets, as is electronic equipment in homes. Random assault is extremely rare. Police sometimes raid parties and lay immorality charges. Since privacy is a paramount consideration in obtaining living quarters, houses with walled gardens have become the standard.