During the IVC, the Ghaggar-Hakra fluvial system was not a large glacier-fed Himalayan river, but a monsoonal-fed river. The Indus Valley Civilisation prospered when the monsoons that fed the rivers diminished around 5,000 years ago, and a large number of sites from the Mature Indus Valley Civilisation (2600-1900 BCE) are found along the middle course of the (dried-up) Hakra in Pakistan. Around 4,000 the Indus Valley Civilisation declined when the monsoons further diminished, and the Ghaggar-Hakra dried-up, becoming a small seasonal river.