The Ganges and Indus Rivers both create deltas. The five main castes in the India Caste System are Brahmin, Kshatriyas, Vaisyas, Sudras, and Harijan. The Himalayan Mountains form a geographic barrier between India and the rest of Asia. Brahmanism developed into Hinduism. The Indian subcontinent includes India, Bangladesh, Bhutan, Maldives, Nepal, Pakistan, and Sri Lanka. King Asoka helped spread Buddhism by encouraging missionary journeys throughout India.