The caste system in India originated around 1500 BC when Indo-European Aryans invaded and divided people into five classes: Brahmins (priests and teachers), Kshatriyas (warriors and rulers), Vaishyas (traders and merchants), Sudras (servants and laborers), and Harijans (untouchables responsible for sanitation work). The caste system enforced social restrictions where people could not marry, interact, or eat with those outside their caste. Lower castes also faced barriers to education, temples, and intergenerational mobility.