The hills of south Baluchistan do not seem to contain evidence of distinct
Harappan settlements. But Dabarkot in north Baluchistan seems to possess a
distinct Harappan level. Considering the accessibility of Afghanistan from
this area, Dabarkot may be a trading or resource-procuring settlement.
The mature Harappan settlement of Shortughai in north-east Afghanistan is a
small (2.5 ha) and isolated site believed to have been a trading colony. Trade
in this context could be based, on the Harappan side, on the lapis lazuli and
rubies of Badakhshan and tin of central Asia and Afghanistan.
On the whole, it is clearly indicated that the basic character of the Indus
settlements was conditioned by factors such as local agricultural geography,
distribution of raw materials and the alignment of inland trade routes. The
Indus civilisation covered not merely a large geographical territory but also a
large segment of time. It began in the Cholistan tract on the bank of the
Ghaggar-Hakra course. A short time after this took place, the civilisation
spread across the Hakra-Indus doab towards Mohenjodaro and other places in
Sind. Radiocarbon evidence indicates that this expansion, as also the
expansion towards Rajasthan, Haryana and Punjab, took place after the phase
of expansion towards the lower Sind, sometime around 2500 BC. Along with
the movement towards the lower Sind there was in all probability another
movement towards Kutch which was then likely to have been an island and
lay virtually at the mouth of the combined Hakra-Indus flow.
    In fact, if one takes into consideration the Rajasthan-Punjab-Haryana
sites, the distribution of the Indus civilisation sites shows the most dense
concentration along the Ghaggar-Hakra course at three points—in Cholistan,
along the Sirhind nala which is a part of the Ghaggar-Sarasvati system in the
Bhatinda area, and in Kutch in the estuary of the combined Ghaggar/Hakra-
Indus flow. The movement towards the Saurashtra peninsula and mainland
Gujarat took place from Kutch, possibly in a somewhat later period.