Third tunnel planned beneath SGNP amidst congestion woes

Mumbai: The city’s green lungs, the Sanjay Gandhi National Park (SGNP), will once again be bored as plans for a third tunnel beneath its expanse move forward. The Mumbai Metropolitan Region Development Authority (MMRDA) is spearheading the project, which includes a part-tunnel, part-elevated road parallel to the congested Ghodbunder Road. Five months after the tender was floated, five infrastructure firms have submitted their bids to execute the project.

The proposed third tunnel joins two other projects beneath SGNP: the 10.8-km Thane–Borivali twin tunnel, managed by the MMRDA, and the 6.3-km Goregaon–Mulund Link Road twin tunnel, handled by the Brihanmumbai Municipal Corporation. Companies vying for the new project include Larsen & Toubro Limited, Megha Engineering and Infrastructure Limited, Navayuga Engineering Company Limited, Afcons Infrastructure Limited, and Rithwik Projects Private Limited. While the estimated cost is pegged at ₹20,000 crore, the final figure will depend on the lowest bid after financial evaluations.

Revised design for better feasibility

Initially, the plan involved a double-decker flyover and an elevated metro rail along Ghodbunder Road. The flyover was to span 4 km between Gaimukh in Thane and Fountain Hotel Junction, forming part of the larger 9.2-km Mumbai Metro 10 corridor connecting Gaimukh to Kashi Mira in Mira Road East. However, the forest department raised concerns about the alignment’s sharp curves, prompting a redesign.

“The twin tunnel approach was adopted to address reservations and enhance feasibility,” an MMRDA official explained. Without the revision, the project would have been the Mumbai Metropolitan Region’s third double-decker metro line, alongside the ongoing Metro 6 (Swami Samarth Nagar to Vikhroli) and Metro 9 (Dahisar East to Bhayander).

The revised plan now includes a 5.5-km underground twin tunnel and a 10-km elevated road. Of the total stretch, approximately 2 km will consist of approach roads for tunnel entry and exit. The tunnel segment will connect Thane’s Gaimukh to Fountain Hotel Junction on the Mumbai–Ahmedabad Highway, while the elevated road will extend from Fountain Hotel Junction to Bhayander.

Addressing congestion on Ghodbunder Road

The project aims to alleviate severe congestion on the existing four-lane Ghodbunder Road, where heavy vehicles often create traffic snarls stretching at least 2 km. The ongoing construction of Mumbai Metro 4 and 4A has further exacerbated the issue, with barricades narrowing the available lanes.

Additionally, a 13.2-km Thane Coastal Road is in the pipeline to facilitate traffic movement towards Bhiwandi, complementing the tunnel and elevated road infrastructure.

Timeline and approval

The tender for the project was floated in July 2024, following approval from then-chief minister Eknath Shinde during an MMRDA authority meeting. The timeline for completing the 15.5-km stretch is 54 months, or 4.5 years. Currently, technical evaluations of the bids are underway, with financial bids expected to be opened in the coming weeks to finalise the contractor.

The project is seen as a crucial step towards decongesting one of Mumbai’s busiest corridors, promising a smoother commute for thousands of daily travellers.