As previously described, the flags of many Persian Gulf states contains large sections of white for historical reasons, while many Arab States in the Middle East, from Sudan to Iraq, have a unique blend of white, red, black and green. Beyond these two themes is the broader common theme between the other Arab states and other states — the color green and the crescent moon. Green has a special place in Islam and is commonly used in the decoration of mosques, the bindings of Qur’ans, the silken covers for the graves of Sufi saints, and in the flags of various Muslim countries. The crescent moon is also an important symbol. The second most important color is red, but that appears to be more cultural than religious.
Notable flags not included in this series are Eritrea, Somalia, Oman and Bangladesh. Eritrea has a flag based on the struggle of its war for independence against Ethiopia. Oman has a flag with similar colors to other Arab states but with a unique emblem and with different reasons for the placement of the colors. Somalia has a simple, light blue flag and one star meant to represent national unity. And Bangladesh, which has a red circle on a green background, similar to the flag of Japan, is not covered in the above map because the green of the flag stands for the lushness of the land of Bangladesh, and is not related to the Islamic religion followed by most of the population.