Why have Pahadi women historically enjoyed freedom from purdah (veil), dowry pressure, gender segregation, and strict patriarchy, unlike women in many other parts of India (including our neighbours) where these were oppressive?

Why have Pahadi women historically enjoyed freedom from purdah (veil), dowry pressure, gender segregation, and strict patriarchy, unlike women in many other parts of India (including our neighbours) where these were oppressive?