Our religion [hinduism] and nation forbids castes. No where in vedas caste is mentioned. A human is a brahmin / sudra not by birth but by the way of life he leads. Ravana is son of a sage but he is a sudra by his deeds. Vishwamitra is a king by birth but he is a brahmin by way of life. Valmiki is a sudra [robber] by birth but a brahmin by his way of life. He wrote ramayan.
So please understand that OBC / SC-ST IS A MYTH. KUDOS TO SUPREME COURT!