PC(The Times of India, Swarajya)
Mumbai is on the cusp of a major infrastructure breakthrough. The Thane-Borivali Twin Tunnel billed as India’s longest urban road tunnel – is about to transform east-west connectivity in the Mumbai Metropolitan Region. With tunnelling work gaining rapid momentum in April 2026, this ambitious project promises to cut the gruelling 1-1.5 hour journey (often stretching to 2 hours in peak traffic) down to a swift 15-20 minutes.
Length: 11.84 km (with approximately 10.8 km underground twin tunnels) Route Connecting Ghodbunder Road in Thane to the Western Express Highway (WEH) in Borivali, passing deep beneath the ecologically sensitive Sanjay Gandhi National Park (SGNP)Design: Two parallel three-lane tunnels (including one dedicated emergency lane each) Implementing Agency: Mumbai Metropolitan. Region Development Authority (MMRDA). Estimated Cost: ₹18,838 crore (including taxes and land acquisition; total project cost may reach up to 20,000 crore with revisions).
Target Completion: May-December 2028 Tunnelling Milestone: “Nayak” and “Arjuna” Lead the Charge a significant milestone is unfolding right now. Advanced Tunnel Boring Machines (TBMs) named “Nayak” – described as India’s largest single-shield hard rock TBM with a 13.34-metre diameter – and “Arjuna” are set to drive the excavation.
“Nayak” is poised for launch in early April 2026 (reports indicate drilling beginning around Monday, April 6), with “Arjuna” following shortly after. These massive machines will bore through challenging geological conditions while minimising surface disruption and environmental impact on the national park above. Construction uses closed conveyor systems for debris removal to reduce pollution, and the tunnels are being built at depths of 23-60 metres for added safety and minimal ecological disturbance.
Game-Changing Benefits for Mumbai Commuters. The current 23-km stretch via Ghodbunder Road is one of Mumbai’s most congested corridors. Once operational, the twin tunnels will deliver. Dramatic time savings: From 60-90+ minutes to just 15-20 minutes. Major congestion relief on Ghodbunder Road and surrounding arterial routes reduced vehicular emissions thanks to smoother, faster traffic flow
Enhanced safety with advanced ventilation. Firefighting systems, smoke detection, LED signage, and cross-passages every 300 metres for emergency evacuation. The project also includes approach roads and supporting infrastructure to seamlessly integrate with the existing road network.
Land acquisition in Thane is largely complete. Rehabilitation of affected families in Borivali is progressing. Launching shafts are ready, and tunnelling excavation is accelerating on the Thane side. MMRDA has highlighted the project as a key step toward “Mumbai in Minutes,” promising a transformed commuting experience across the region this ₹18,838-crore initiative is among the most complex and expensive urban tunnelling projects in India. By using state-of-the-art TBM technology in an eco-sensitive zone, MMRDA aims to balance ambitious infrastructure goals with environmental responsibility.
Once completed, the Thane-Borivali Twin Tunnel won’t just ease daily commutes – it will reshape how people live, work, and travel in the Mumbai Metropolitan Region, unlocking new economic and residential opportunities on both sides of the city. Mumbai is literally digging deeper for a brighter, faster future. Stay tuned as “Nayak” and “Arjuna” begin carving this underground milestone.