Tehran is sometimes effectively shut down due to the pollution levels and some estimates put the number of deaths caused by pollution there at 3,600 per month.
Iran is heavily energy intensive but with fuel subsidies amounting to a staggering 20% of GDP, it is no surprise that Iranians over-consume it. Unsurprisingly, analyses show that fuel subsidies are bad for the environment and are unsustainable from a development perspective. Thankfully, there have been large recent reductions in Iran.
Nonetheless, Abbas Milani thinks that one of the toughest questions journalists could as President Ahmadinejad is on his government's neglect of some environmental issues:
"Your government has been oblivious to the grave ecological dangers faced by your country. The Zayandeh Rude River in Isfahan has dried up; the drying up of Lake Orumiye will affect the lives of hundreds of thousands of Iranians living in the area. Why have you, in spite of your much-touted trips around every province, ignored these grave problems?"
Taken from the Wikipedia article on Lake Orumiye, here are satellite images of the rapid shrinking of the lake between 2003 and 2010: