Rise of the Indus Valley Civilization

The Indus Valley Civilization entered its mature urban phase around 2600 BCE, when earlier village-scale Early Harappan communities in the Indus river basin grew rapidly into large, sophisticated cities, a transformation that continued until roughly 1900 BCE. Its major urban centers, including Mohenjo-daro in the lower Indus valley and Harappa in western Punjab, each may have housed between 30,000 and 60,000 people at their height, laid out on planned grid systems with baked-brick construction and what is considered the world's first known system of covered civic drains and household sanitation. Further cities, including Dholavira in western Gujarat and Rakhigarhi in Haryana, extended the civilization's reach across a geographic area that, by most estimates, was more extensive than contemporary Egypt and Mesopotamia combined, making it one of the four great cradles of early urban civilization alongside those two regions and ancient China. Archaeological evidence suggests a relatively uniform, egalitarian access to civic infrastructure such as water and sewerage across Indus cities, though the civilization's script remains undeciphered, leaving much about its political and social organization still a matter of scholarly reconstruction.