The Indus Civilization flourished between about 2600 and 1800 BC when it collapsed into regional cultures at the Late Harappan stage. According to Parpola the collapse was due to a combination of several factors like over-exploitation of the environment, drastic changes in the river-courses, series of floods, water-logging and increased salinity of the irrigated lands. Finally
the weakened cities would have become easy victims of the raiders from Central Asia, whose arrival heralded a major cultural discontinuity in South Asi