The Mumbai Metropolitan Region Development Authority’s (MMRDA) Orange Gate–Marine Drive underground road tunnel has achieved a significant construction milestone, with excavation crossing approximately 650 metres nearly five months after the start of the main tunnelling phase.
The project, regarded as one of India’s deepest and most technically demanding urban road tunnels, is expected to play a crucial role in strengthening Mumbai’s underground transport network.
Main excavation began on February 28, 2026, after the successful completion of the initial tunnelling drive and commissioning of the Tunnel Boring Machine (TBM). Since then, the slurry shield TBM has steadily advanced through Mumbai’s challenging coastal geological conditions, taking the excavated stretch to around 650 metres.
The project was inaugurated on December 3, 2025, by Chief Minister Devendra Fadnavis and Deputy Chief Minister and MMRDA Chairman Eknath Shinde. The TBM, among the largest deployed for an urban road tunnel in India, commenced its initial tunnelling drive on January 8, 2026, before transitioning to full-scale excavation at the end of February.
The Orange Gate–Marine Drive project comprises twin underground tunnels spanning more than 7 km, with the first tunnel currently under construction measuring approximately 3.45 km. The alignment descends to nearly 52 metres below ground level, passing beneath the Central and Western Railway corridors as well as Mumbai Metro Line 3, making it one of the most complex tunnelling projects undertaken in the country.
Once completed, the tunnel is expected to reduce travel time between Orange Gate and Marine Drive to around five minutes. It will also create a high-speed east-west corridor connecting South Mumbai with major transport infrastructure, including the Mumbai Coastal Road and the Mumbai Trans Harbour Link (Atal Setu).
Officials said the underground corridor is expected to ease congestion on existing roads, improve the movement of freight and passenger traffic across South Mumbai, while also reducing fuel consumption and vehicle emissions through a faster, uninterrupted route.
Project Timeline
- December 3, 2025: Project inaugurated and TBM launched
- December 2025–January 2026: Installation of backup systems, hydraulic and electrical connections, and sensor calibration
- January 8, 2026: Initial tunnelling drive begins
- January 26, 2026: Permanent tunnel ring installation starts
- January 31, 2026: Initial tunnelling drive completed
- February 26, 2026: Transition to the main excavation phase
- February 28, 2026: Full-scale tunnelling commences
- March 26, 2026: Excavation reaches 70 metres
- July 2026: Tunnel excavation crosses approximately 650 metres, marking a major milestone in the construction of one of Mumbai’s most ambitious underground road infrastructure projects.
Source: The Free Press Journal
