What are the three main ancient civilizations in India?

The three main ancient civilizations in India are the Indus Valley Civilization, the Vedic Civilization, and the Maurya Empire. The Indus Valley Civilization, known for its advanced urban planning and trade, flourished around 2500 BCE in present-day Pakistan and northwest India. The Vedic Civilization, emerging around 1500 BCE, is characterized by the composition of the Vedas and the establishment of social hierarchies. The Maurya Empire, which reached its height in the 3rd century BCE under Ashoka, is notable for its political unification and promotion of Buddhism.