Its second tunnel boring machine, adding capacity to excavation beneath the Sanjay Gandhi National Park. The development strengthens the project’s prospects of creating a direct east-west road connection between Thane and Borivali, potentially cutting journey times while limiting the need for major surface-road expansion. The Mumbai tunnel project spans about 11.84 km, including 10.25 km of underground construction and 1.59 km of approach roads. The alignment will connect Ghodbunder Road on the Thane side with the Western Express Highway at Borivali. According to the Mumbai Metropolitan Region Development Authority (MMRDA), the route could reduce the existing journey by about 12 km and save roughly an hour under typical conditions.
The second machine, Arjuna, joins Nayak, which began excavation earlier from the Thane side. Recent reporting confirms that Arjuna has now been launched, allowing work on the two tunnel tubes to progress in parallel. This is important for a project whose construction programme depends heavily on maintaining momentum across a technically difficult underground alignment. For commuters, the headline benefit is the possibility of reducing a road journey that can currently take 60 to 90 minutes to around 15 minutes. The Mumbai tunnel project could therefore alter travel patterns between the western and eastern parts of the metropolitan region. It may also improve access between employment districts and residential areas, reducing the time burden currently imposed by congested surface routes. The engineering challenge, however, is substantial. The tunnels will pass beneath the national park, with the deepest section reaching significant underground depths.
MMRDA says the project has received the required forest and wildlife-related clearances and that underground construction is intended to limit disturbance at the surface. The official design provides two tunnel tubes, each carrying two traffic lanes and an emergency lane, with cross-passages planned at regular intervals. That environmental dimension will remain central as excavation advances. Underground construction can reduce direct disruption to protected landscapes, but it does not remove the need for careful monitoring of groundwater, geology, biodiversity and construction impacts. The project has also involved rehabilitation of people affected by works on the Borivali side, making timely resettlement an important part of responsible infrastructure delivery. The project carries a sanctioned cost of about ₹16,600 crore, while MMRDA reported physical progress of 11.49% as of March 2026. Its eventual value will depend not only on faster road travel but on how effectively it connects with existing public transport and manages additional traffic demand.
For Mumbai Metropolitan Region, the next test is therefore execution. Faster connectivity can support economic activity and reduce wasted travel time, but the Mumbai tunnel project will deliver its strongest urban benefit only if it forms part of a wider, integrated and environmentally responsible transport system.
