This separates the two genders from each other in all aspects of Middle Eastern culture. Women are restrained from participating in many of the activities in which males are prevalent.
Purdah is evident in the Islamic world, but is also observed by other communities in the Indian subcontinent. The usual garment worn is a Burqa, which may or may not include a Yashmak, a Veil to conceal the face. The eyes may or may not be exposed.
Purdah was rigorously observed under the Taliban in Afghanistan, where women had to observe complete purdah at all times when they were in public. Only close male family members and other women were allowed to see them out of purdah. In other societies, purdah is often only practiced during certain times of religious significance.
In historically Islamic Arab countries, such as Saudi Arabia, purdah has more cultural than religious significance, being a custom. Even in the United Arab Emirates, where women can wear skirts and similar modest garments, Arab women often observe purdah.
A form of purdah is also seen in other religions such as Christianity and Judaism. Certain Christian and Jewish denominations require women to be 'covered' whilst worshipping (if only by a hat or similar symbolic object).