I got this much from someone else: For many years, Indians followed a custom called “purdah,” the practice of concealing women to “protect them from the lustful gaze of men -- an idea that came from the Arab invaders. This is why palace after palace contains stone screens so that women can get a (fractured) glimpse of the world without ever being seen.

A Maharini once visited London, but she remained hidden from view. She was always transported in a curtained car and a covered palanquin. As you can imagine, the English press went wild trying to get a photo of her, but all they got was a glimpse of her ankle. The Hindu royalty was so furious about this photo of their Maharini’s ankle that they bought and destroyed every single issue of the newspapers that would have exposed her ankle to the world.

but not a great source

http://www.fodors.com/community/asia/a-month-in-india-360761-2.cfm