So one theory for the collapse of the IVC (the Harappan Civilization)is that the slow eastward migration of the monsoons across Asia initially allowed the IVC to develop, but as the monsoons kept shifting eastward, the water supply for the agricultural activities dried up and the monsoon-supported farming of the Harrapan civilization resulted in the IVC being forced eastwards into smaller more spread out farming settlements that could not support the cities of old. So lets assume that this theory is correct and that the shifting migration of the monsoons led to the decline of the Harappan Civilization. Is there some form of irrigation that could have been adopted to save the IVC, perhaps Mesopotamian irrigation develops that prevents the need to move eastwards? With a surviving and much better off IVC what might occur then the Indo-Europeans arrive on the scene?