In India, ports are divided into two categories: major and non-major ports.

Option 1, Kochi (Cochin), is incorrect because it is a major port in India. It is located in the state of Kerala and is known for facilitating the export and import of goods, making it a crucial part of India`s maritime trade.

Option 3, Paradip, is also incorrect as it is a major port. Located in the state of Odisha, Paradip is one of the oldest operational ports in India and handles a significant volume of cargo.

Option 4, New Mangalore, is incorrect too because it is a major port. Situated in Karnataka, it`s a deep-water, all-weather port and serves as an important gateway for the maritime trade of the south and central parts of India.

This leads us to Option 2, Dahej, which is the correct answer. It is a non-major port located in Gujarat. While it may not handle as much cargo as the major ports, it still plays a crucial role in regional trade and commerce.