In the very least, India will invest $500m in the construction and will be the operator of the port near the border with Pakistan. The port will be the gateway of India to Central Asia and Russia via Afghanistan. On the other hand, India will be able to use it to import Iranian oil to satisfy its growing energy demands.
Also, the new port will have a significant geo-strategic importance for India in terms of opposition to China. Since China built the deep-water port of Gwadar in Pakistan and supports the country with economic projects, India needs to create some balance. Pakistan and India have complicated relations with high tensions, so India could only expand the zone of influence in the Western Indian Ocean with Iran. In addition, the new port will give India rationale for expanding their naval forces and the deployment of warships in the area close to the Iran-Pakistan border.
Narendra Modi is a native of Gujarat. In the past he has held the post of governor of the state, and contributed to investment and infrastructure development. The distance from the port of the future on the Iranian coast to Gujarat is less than the distance between New Delhi and Mumbai.
With regards to Iran, following a visit to the country, an agreement on cooperation in the field of aeronautics, biotechnology, nanotechnology, as well as counter-terrorism activities was signed.