The decline of Indus civilisation, it lost its urban characteristic. There are different views by different historian about the decline of Indus civilisation. Some considered it as the result of war with the Aryans. Some considered the tectonic uplift is the major reason behind the decline of civilisation. According to Lambrick the reason behind the decline was the change in the course of Indus River as they totally depend on river, the change of course become the reason behind decline. A few historians think that the ecological degradation is the major cause of decline.