Caste is very much alive among Muslims and Christians in India. Its a social system not religious.
Moslem buddy of mine from Pakistan said "Don't let them fool you. Everyone still knows his own caste and history. You couldn't get married if you didn't."
Caste is a fundamental part of Hinduism. In fact, some Hindu “religious” scriptures are little more than glorifications of the conquest of the dark-skinned people by the Aryan invaders. Neither Islam nor Christianity have caste as an integral part of their culture. If that were not so, why would Dalits be so inclined to convert to Christianity, more than other groups?