Mumbai’s ambitious underground mobility network has achieved a significant breakthrough, with the Orange Gate-Marine Drive road tunnel project entering its main tunnelling phase, according to the Mumbai Metropolitan Region Development Authority. The development marks a crucial step forward in one of India’s most complex urban infrastructure projects aimed at transforming east-west connectivity in the city.
Main drive signals key progress
The project recently crossed an important milestone as the Tunnel Boring Machine (TBM) commenced its main drive operations after successfully completing the initial excavation phase, the Mumbai Metropolitan Region Development Authority stated. Designed specifically to tackle Mumbai’s challenging coastal geology, the TBM – the largest slurry shield machine deployed for an urban road tunnel in India – has already demonstrated strong performance.
The authority noted that following an earlier breakthrough, the machine has advanced rapidly, excavating nearly 70 metres within just a few days, reflecting both engineering precision and operational efficiency.
Big milestone for Mumbai’s Underground Mobility Project: Orange Gate–Marine Drive Tunnel Begins Main Drive
The Orange Gate–Marine Drive Road Tunnel, one of India’s most complex urban road tunnelling projects, has reached another historic milestone with the main tunnelling drive… pic.twitter.com/AcwSKqI4lk
— MMRDA (@MMRDAOfficial) March 27, 2026
High-level backing and strategic importance
The TBM was officially launched on December 3, 2025, in the presence of Chief Minister Devendra Fadnavis and Deputy Chief Minister Eknath Shinde. The project is being implemented by the Mumbai Metropolitan Region Development Authority and is considered a critical component of the city’s long-term transport infrastructure strategy.
Engineering marvel beneath the city
According to the Mumbai Metropolitan Region Development Authority, the project involves the construction of twin tunnels stretching over 7 kilometres. The first tunnel, currently under development, spans 3.45 kilometres and reaches depths of up to 52 metres below ground level. The alignment passes beneath key transport corridors, including Central Railway, Western Railway, and Mumbai Metro Line 3, requiring high levels of safety and engineering precision.
The authority stated that once completed, the tunnel will reduce travel time between Orange Gate and Marine Drive to just five minutes. It will also provide seamless integration with major infrastructure such as the Coastal Road and Atal Setu, significantly easing congestion and reducing fuel consumption and vehicular emissions.
Milestones achieved so far
The Mumbai Metropolitan Region Development Authority highlighted that since its launch, the project has recorded steady progress through multiple critical stages. These include the successful lowering and installation of the TBM’s backup system, integration with the TBM shield, and completion of essential hydraulic and electrical connections.
The authority further noted that advanced monitoring instruments such as flowmeters, densitometers, and pressure sensors were calibrated to ensure safe and efficient operations.
The initial tunnelling phase began on January 8, 2026, with the erection of temporary rings, followed by permanent ring installation starting January 26. The initial drive was completed by January 31, paving the way for the transition to the main drive, which was finalised on February 26. Full-scale tunnelling operations officially commenced on February 28, the authority said.
Rapid progress continues
As of March 26, 2026, the TBM has excavated 70 metres out of the planned 3,720 metres for the first tunnel, the Mumbai Metropolitan Region Development Authority said, adding that the pace of work is expected to accelerate in the coming months.
The Orange Gate–Marine Drive tunnel is poised to become a game-changer for Mumbai, offering faster, more efficient connectivity while supporting the city’s vision of sustainable and modern transport solutions, the authority added.
