Silt accumulation presents a considerable challenge for certain ports owing to their geographical positioning and the sediment-depositing river systems. Considering the provided options:
- Mumbai port - Situated on India's west coast, its coastal location and deep natural harbour mitigate significant silt accumulation concerns.
- New Mangalore port - Also located on the west coast, its primary function is handling cargo such as crude oil, and it does not experience substantial silt accumulation.
- Kolkata port - Positioned on the east coast near the Hooghly River's estuary, this port is well-known for its siltation problems. As a riverine port, it is heavily impacted by sediments from the Ganges-Brahmaputra river system.
- Paradwip port - Located on the east coast, this port predominantly handles cargo like iron ore and does not contend with the severe siltation issues affecting river ports such as Kolkata.
The accurately identified port is: Kolkata port, attributable to its location on a river characterized by substantial sediment flow.