Which (replying to Talinthas) raises this question: What would the subcontinent be like if the Harrappans had not faded away?
Background: The Harappan civilization in the Indus Valley arose at a time when the climate was a bit more salubrious. But conditions didn't last, and as the local climate deteriorated the Harrappans were unable to maintain a level of agriculture sufficient to keep their cities fed. With the lower standard of living, and the lack of adequate nutrition diseases took their toll, and the Harrappan cities were abandoned.
Right about the time the Indo-Aryan tribes migrated down out of Central Asia. A place that had once been nicer to live in, and able to support a larger population itself. As the nomads moved into Harrappan territory they found scattered villages and bands living on the edge, in the middle of great abandoned cities. They also encountered the local diseases, which lead to a strict segregation for health reasons, and the foundation of India's caste system.
Later, with advances in agriculture, government, and transportation of goods the Indus Valley would once again become a bread basket. But these changes would take centuries.
But what if the Harappans had made those adaptations themselves? With if the advances in agriculture had come when the climatological changes first began. What if the Indo-Aryan tribes had been forced west to join fellow tribes in Iran, or east around or through Tibet into the land we know call China?
Or (making this a fantasy setting), what if Harrappan shamans and priests had developed the magic needed for the altered climate? Magics crafted to ensure good yields. Somehow making Harrappan crops able to thrive under the new conditions.
However it happens, how do you see India developing over the ages?
