The Orange Gate–Marine Drive tunnel is a 9.96 km underground road corridor being developed at an approved cost of Rs 80.56 billion (bn), with nearly seven km of the alignment comprising twin tunnels linking Orange Gate near the Eastern Freeway with Marine Drive. Designed as a high-speed underground route, the corridor will integrate with the Mumbai Coastal Road and the Mumbai Trans Harbour Link to improve freight movement and commuter mobility. Each tunnel is planned to accommodate two traffic lanes plus an emergency lane and to support vehicle speeds up to 80 kmph.
Excavation is being carried out using a 12.19-metre slurry shield tunnel boring machine chosen for the alignment’s subsurface conditions, which include densely populated neighbourhoods and high groundwater. The alignment passes beneath critical transport corridors, including the Central Railway, Western Railway and Metro Line 3, at depths ranging from around 12 metres to nearly 52 metres, adding to engineering complexity. MMRDA reports the project has achieved around 14 per cent physical progress to date.
The corridor will incorporate cross passages, mechanical ventilation, fire-resistant infrastructure, intelligent traffic management systems and modern lighting to enhance operational safety and resilience. The authority anticipates that diverting through traffic into the tunnel will substantially ease congestion on surface roads, with travel time between Orange Gate and Marine Drive expected to reduce to about five minutes and overall journeys across South Mumbai cut by up to 20 minutes. The project forms part of MMRDA’s broader strategy to expand underground transport infrastructure and to support the city’s long-term mobility requirements.