In early February 2026, India's first underwater metro line opened in Mumbai, running under Mahim Bay. The project, which took nearly 10 years to build, has become one of the most technologically complex in the history of Indian infrastructure. The line connects the districts of Colaba, Bandra, and Seepz, reducing travel time from 70 minutes to 22.

The 1,8-kilometer underwater section was constructed using a specialized tunnel boring machine capable of operating under high pressure. Engineers note that the project posed a challenge for the entire industry: challenging soil conditions, high seismic activity, and the need to protect the marine ecosystem required innovative solutions.

For tourists, the new line provides quick access to key areas of the city, including Marine Drive, the historic center, and the Bandra-Kurla business district. Authorities expect the metro's launch to reduce traffic congestion and improve the city's environmental situation, where air pollution levels remain among the highest in Asia.

Experts believe the project will serve as a model for other coastal cities facing traffic congestion and a lack of space for land-based infrastructure.