The caste system in India is a social hierarchy that divides society into groups determining one's occupation and spiritual purity based on birth. Placement in the social hierarchy is determined by one's parents' caste, and people cannot change their caste during their lifetime. It is based on the Hindu belief that righteous living leads to reincarnation into a higher caste, while wicked living leads to a lower caste. At the bottom of the system are the "untouchables" who are completely ostracized from society and can only perform the most menial jobs.