African Presence in Early Asia presents an essay by Indian activists v. They call themselves Dalits which means crushed and broken. The problem is the sanctioned oppression of Black Untouchables. The caste structure maintains itself because every member of a particular caste group stands to gain by belonging to that particular caste-group. The caste system helps the exploitation of the weark by the strong.
Caste system is based on purity and pollution.
One group is considered more pure than the other. The less pure caste group accepts its lower status because it is happy that it has a much larger caste group below it to exploit. As long as there is somebody below it to exploit, it is proud and will not mind somebody always standing on its shoulders. India's Blacks are ignorant of their African roots. India's native Black population is the largest Black population outside Africa, numbering about 200 million.