Gita preaches (IV .39-40) Karma theory. Krishna tells us in the Gita that he is the author of the caste system (Gita 4-13, 10-36, 41). The Upanishads have also sanctioned the caste system those who are of pleasant conduct here - the prospect is, indeed, they will enter a pleasant womb, either the womb of a Brahmin, or the womb of a Ksahtriya, or the womb of a Vaishya. But those who are of stinking conduct here- the prospect is indeed, that they will enter a stinking womb, either the womb of a dog or the womb of a swine or the womb of an outcaste (Shudra).. (Chandogya Upanishad .5-10-7).
These Brahmins have created untouchability among Indians so that they can easily divide and rule over India and they have succeeded in it.