Which one of the following sea routes is the shortest from point to point?

The shortest sea route among the given options is Chennai to Port Blair. According to official maritime data and maps, the distance from Chennai to Port Blair is approximately 630 to 700 nautical miles (roughly 1,167 to 1,300 km). In comparison, the route from Kolkata to Yangon is approximately 790 nautical miles . The distance from Kolkata to Chennai is significantly longer, as it involves navigating the coastline of the Bay of Bengal, covering approximately 1,684 km by land and even more by sea due to the riverine nature of the Kolkata port . The Mumbai to Colombo route is part of the major Suez-Colombo international shipping lane [3], covering a distance of approximately 890 nautical miles. Therefore, the direct crossing from Chennai to Port Blair represents the shortest point-to-point distance among the listed maritime routes.

Sources

1. [1] https://www.indianembassytehran.gov.in/public_files/assets/pdf/rails_sea_india.pdf
2. [3] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 12: Transport, Communications and Trade > Ports > p. 20