You know, one thing that might help us outsiders is, what actually is the caste system? Is it based on race (skin color), lineage (surnames) or some geographic

You know, one thing that might help us outsiders is, what actually is the caste system? Is it based on race (skin color), lineage (surnames) or some geographical criteria (article mentioned "do you swim" like maybe being near the ocean means you're better off or something)?! Seriously, what are the hierarchical structures and how deep does it go.