Assertion: The British used the ports as suction points for the resources from their hinterlands.
Reasoning: The extension of railways towards the interior facilitated the linking of the local markets to markets all over the country to drain the resources to ports.

Both Assertion (A) and reasoning (R) are correct and R is the correct explanation of A.

The British used the ports as suction points for the resources from their hinterlands. The extension of railways towards the interior facilitated the linking of the local markets to regional markets, regional markets to national markets and national markets to the international markets. This trend continued till 1947. It was expected that the country’s Independence will reverse the process, but the partition of the country snatched away two very important ports, i.e., Karachi port went to Pakistan and Chittagong port to the erstwhile east Pakistan and now Bangladesh. To compensate for the losses, many new ports, like the Kandla in the west and the Diamond Harbour near Kolkata on river Hugli in the east were developed.