The archaeological remains show that before the emergence of Harappan civilization the people lived in small villages. As the time passed, there was the emergence of small towns which ultimately led to full-fledged towns during the Harappan period.
The whole period of Harappan civilization is in fact divided into three phases:
The archaeological excavations reveal that this culture was spread over a vast area which included not only the present day states of India such as Rajasthan, Punjab, Haryana, Gujarat, Maharashtra, Western Uttar Pradesh but also Pakistan and some
parts of Afghanistan.
Some important sites of this civilization are: Manda in Jammu and Kashmir; Shortughai in Afghanistan; Harappa in Western Punjab (Pakistan); Mohenjodaro and Chanhudaro in Sind; Kalibangan in Rajasthan; Lothal and Dholavira in Gujarat; Banawali and Rakhigarhi in Haryana; Daimabad in Maharashtra while Sutkagendor on the Makran Coast (near Pakistan-Iran border) is the western most site of the Harappan civilization and Alamgirpur in western Uttar Pradesh marks its eastern most limit.
The location of settlements suggests that the Harappa, Kalibangan (On R Ghaggar-Hakra generally associated with the lost river Saraswati), Mohenjodaro axis was the heartland of this civilization and most of the settlements are located in this region. This area had certain uniform features in terms of the soil type, climate and subsistence pattern. The land was flat and depended on the monsoons and the Himalayan rivers for the supply of water. Due to its distinct geographical feature, agro-pastoral economy was the dominant feature in this region.
Besides the urban settlements of the Harappans, there were many sites inhabited by the primitive communities consisting of stone-age hunter-gatherers or pastoral nomads, which existed side by side. Some sites served as ports or trading out-posts.
The important determinants of urbanisation are well-planned cities, specialised arts and crafts, trade, taxation, script, etc. In this respect Harappan culture fulfilled all these criteria for being called as an urban culture.