The country started being run by Islamic religious political party.
Explanation:
Until the 1970's, Iran surprisingly was pretty liberal when it came to the rights of women. This lasted for several decades, and the main reason was that the country had a ruler that wanted to make the country more liberal and implement Western values.
This sharply ended in the 1970's, when on power came politicians with Islamic ideology. This change immediately affected the women negatively. From being free to do their own choices, as well as being equal to men, they suddenly found themselves in a situation were the laws made them subordinate to men. For most things they became citizens of second class. The freedom of choice disappeared, and they had to cover themselves with traditional clothes, so instead of going forward they were set several centuries backwards.
