Decline of the Indus Civilization and the Rise of Vedic Society

Beginning around 1900 BCE, the great Harappan cities entered a gradual process of decline, marked by the abandonment or shrinking of urban centers, the disappearance of the Indus script and of metric standardization, and growing regional cultural fragmentation. Modern research attributes this decline chiefly to climatic change — a weakening of the summer monsoon and the progressive drying of the Ghaggar-Hakra river, possibly the Sarasvati celebrated in Vedic hymns — combined with shifts in trade routes and internal socioeconomic reorganization, rather than to any single catastrophic event. The old theory that "Aryan invaders" violently destroyed the Indus civilization, popularized in the mid-twentieth century by Mortimer Wheeler on the basis of skeletons found at Mohenjo-daro, has been discarded by later research, which reassessed those remains as unconnected to any single violent episode; most specialists today prefer the term "decline" to "collapse," stressing its gradual, regionally uneven character.