Answered by Sidi Moustafa Elqabbany
A woman wears jilbab till her feet. However when she goes into sajdah her feet are visible. Is her salah valid. Also, what is the ruling on salah for a woman who wear shalwar kamees (traditonal dress of Indian subcontinent).

In the Name of Allah, Most Merciful and Compassionate
A woman’s `awrah in prayer is her entire body except for her face and hands. Covering the `awrah is a condition of prayer, meaning that it has to occur before the prayer begins and last for the entire duration of the prayer. Thus, in the case that you mention, the woman’s prayer would be invalid. If following the Shafi’i school in this matter would entail her having to repeat a large number of prayers, she can inquire about the ruling in another school. The Hanafi school might be more lenient in this matter, but she should ask those qualified to teach Hanafi fiqh.
As for wearing the shalwar kamees, if it fulfills the requirements of covering the `awrah, then it is acceptable; otherwise, it is not. Any substance that conceals the colour of the `awrah under normal light is acceptable.
Additionally, if the woman is praying where no one can see her, it is disliked for her to wear something that exposes the shape of her `awrah. If others can see her, it is forbidden for her to do so.
Allah the Exalted knows best.
Moustafa Elqabbany
Metro Vancouver, Canada