The reason why Indian women have long hair is because of the way they take care of the hair.
Shampoos and chemical hair products have flooded India only in the recent times and most Indian women still use herbal products to take care of their hair.
They oil their hair and massage their scalp at least once a week which hastens hair growth, and keeps it healthy.
Recent changes though in Indian Fashion, supports the use of short hair by women, which in the long term may affect availability of long healthy, virgin hair.