MMRDA advances a 70-km, Rs 1.05-trillion underground tunnel network as Mumbai's 'third mode' of mobility

MMRDA is advancing detailed project planning for an integrated underground tunnel road network across Mumbai, estimated at around Rs 1.05 trillion and spanning roughly 70 km. Pitched as a "third mode" of mobility beneath the city's roads and metro, it is to be built in three phases — a Worli-to-airport link, an east-west connector and a longer north-south corridor — with feasibility and DPR work moving forward through 2026.

The network is designed to stitch together the Coastal Road, the Bandra-Kurla Complex, the bullet-train terminus and Chhatrapati Shivaji Maharaj International Airport into a single high-capacity underground spine. Together with the Coastal Road, the metro and surface expressways, the authority frames it as the final layer of a tiered mobility plan for the region.

If realised, tunnels of this scale would reorder travel times across the island city and its eastern and northern approaches — exactly the kind of connectivity shift that has historically reset land values along an alignment. BKC and the airport zone, already the city's costliest commercial nodes, would sit at its heart.

The caveats are real: the project is at the planning and feasibility stage, the cost is vast, and alignments, funding and timelines can all change before any boring begins. It belongs on the long-term watch-list rather than the near-term pipeline — but its sheer scale makes it one to track.