The grading system Dr Toole's implying originated with the Indians themselves. Migration after the flood, East from Babel, must have been in two waves. Migrants from Africa
crossed the straits of Bab al-Mandab
and Hormuz
to settle in India
but later migration from elsewhere provided a ruling caste and rigid prejudice against the earlier wave from Africa who, presumably, were descended from Ham.
There must have been hybrids over the centuries though because high caste Indians are readily distinguished from the rest among themselves. They can detect descendants of the former wave of migrants a mile off and, where they're allowed to work at all, assign them to latrine attendant duties. Marriage is completely off the table. No doubt they could arrange something in another country but lips would still curl and eyebrows arch.