A Birthday in Iran, 1973
It could be difficult to conceive at present, but Iran had relatively liberal social norms in the past. This photo, taken in 1974, depicts a woman wearing whatever she pleased, which was acceptable at that time. Additionally, religion had a lesser impact on legislation in comparison to its current influence. Of course, the revolution happened in response to the corruption of the shah, and everything took a turn for the more conservative.
However, photos of women dressed in Western-style clothing like this were common before the revolution. Presumably, this woman celebrated her birthday at her residence in Tehran, and there were likely guests in attendance as she blew out the candles on her cake.