<P> Indian Ocean Trade has been a key factor in East--West exchanges throughout history . Long distance trade in dhows and sailboats made it a dynamic zone of interaction between peoples, cultures, and civilizations stretching from Java in the East to Zanzibar and Mombasa in the West . Cities and states on the Indian Ocean rim were Janus - faced . They looked outward to the sea as much as they looked inward to the hinterland . </P> <P> There was an extensive maritime trade network operating between the Harappan and Mesopotamian civilizations as early as the middle Harappan Phase (2600 - 1900 BCE), with much commerce being handled by "middlemen merchants from Dilmun" (modern Bahrain and Failaka located in the Persian Gulf). Such long - distance sea trade became feasible with the development of plank - built watercraft, equipped with a single central mast supporting a sail of woven rushes or cloth . </P>

The collapse of the gave a boost to indian ocean trade