TL;DR
Casteism is an Organized mafia in India since 700 BC https://archive.is/PdiUF
BC/SC/ST people, 80% in India, were denied education/employment and basic human rights for 2700+ years as per https://en.wikipedia.org/wiki/Rigveda in https://en.wikipedia.org/wiki/Timeline_of_Indian_history
In 1932 https://en.wikipedia.org/wiki/B._R._Ambedkar, Architect of the Constitution of India demanded a separate country (not Reservations/Affirmative Action) for them https://en.wikipedia.org/wiki/Communal_Award
https://en.wikipedia.org/wiki/Mahatma_Gandhi opposed it, bullied and bribed them with https://en.wikipedia.org/wiki/Poona_Pact