Step 1: Environmental causes. One major cause was climatic change, including drying up of rivers like the Saraswati and reduction in rainfall, which affected agriculture.
Step 2: Natural disasters. Frequent floods and possible earthquakes may have destroyed settlements and forced people to migrate.
Step 3: Decline in trade. The decline of trade relations with Mesopotamia reduced economic stability, weakening the civilization.
Step 4: Evidence of collapse. Archaeological evidence shows abandoned cities, poorly built houses in later phases, and reduction in urban planning standards.
Step 5: Cultural changes. There was a shift from urban to rural life, indicating gradual decline rather than sudden destruction.
Step 6: Conclusion. Thus, the collapse of the Harappan civilization was due to a combination of environmental, economic, and social factors supported by archaeological evidence.
