The time of Islamic festivals is calculated according to local sightings of various phases of the moon and the dates given below are approximations which are subject to change each year.
There is a vastly extended network of rivers in Iran most of which seasonally are filled with water. Some permanent rivers run from the Alborz or the Zagros to the Caspian Sea, Persian Gulf and Oman Sea.
Iran scores poorly on the regional MENA ranking, coming in as number 15 among 22 countries. Iran scores low on most factors, and the doctor density is surprisingly low for a country with 130 universities.