Instructions: The answer to this question can be given by writing the time since the Harappan civilization started declining together with giving all probable reasons for the decline.
Solution: The Harappan civilization began to decline by 1900 BCE.Various views have been given by the scholars on the cause of its decline. Some argue that the Harappan civilization declined due to the invasion of Aryans. But this view has no evidence to support and is now discarded.Some scholars believe that continuous flooding caused by the river Indus and its tributaries might have destroyed the Harappan civilization.It is also assumed that the drying up of the river Sarasvati by 1900 BC might have forced the Harappans to migrate eastwards towards the Gangetic plains.