The Indus Valley region was one of three early cradles of civilisation in the Old World; the Indus Valley civilisation was the most expansive,[3] and at its peak, may have had a population as high as five million.[40]
The civilisation was primarily centred in modern-day Pakistan, in the Indus river basin, and secondarily in the Ghaggar-Hakra River basin. The mature Indus civilisation flourished from about 2600 to 1900 BCE, marking the beginning of urban civilisation on the Indian subcontinent. It included cities such as Harappa, Ganweriwal, and Mohenjo-daro in modern-day Pakistan, and Dholavira, Kalibangan, Rakhigarhi, and Lothal in modern-day India.