- Assertion (A) is accurate; Kolkata port's significance has diminished recently. Previously a vital trade hub, its prominence has decreased due to factors such as siltation and evolving trade routes.
- Reason (R) is also factual. Kolkata port struggles with silt accumulation in the Hugli river, impairing navigability and its capacity to accommodate large vessels. This issue significantly contributes to its declining importance.
Therefore, both statements (A) and (R) are correct, with (R) accurately explaining (A).