What happened c. 1500 BCE??

It was proably the marauding Aryan horsemen responsible for the collapse of the Indus Valley civilization or maybe the drought and a fall-off in trade slowly kill the Harappan culture. Historians are also still not sure of the reason behind the fall of the collaspe of te Indus Valley civilisation. Historicans have discovered that the aryan might have attacked the Indus Valley Civilisation and their defence fell cause the death of many people leading to the fall. It might also be the people of the civilisation stopped trading a certain reason thus killing the Indus VAlley Culture.