Mumbai, Jul 15 (IANS): With the detailed project report completed and land acquisition started, the work on building India's longest (11.80 km) road tunnel linking Thane-Borivali - passing beneath the Sanjay Gandhi National Park (SGNP) - will start from March 2022, Maharashtra PWD Minister Eknath Gaikwad said on Thursday.

The Maharashtra State Road Development Corporation (MSRDC) project, which will comprise a 10.25 km double tunnel and 1.55 km junction, is slated to cost around Rs 11,235 crore and expected to be completed in about 66 months.

The 6-lane twin tunnel (3 lanes in each direction) will enable vehicles to zip at 80-kmph and slash the travel time, from the current 60 minutes to barely 15 minutes, between Borivali on the Western Express Highway to Thane, besides decongesting the Ghodbunder Road, Shinde said.

The twin tunnel will run underneath the lush green SGNP for which the MSRDC is taking special precautions to avoid causing harm to its biodiversity or its flora and fauna, which includes leopards, spotted deer, Sambar, civets, different types of monkeys, Indian flying fox, pythons and other snakes, big and small reptiles including crocodiles, birds, insects, thousands of plant species, etc.

For this, the MSRDC will deploy Tunnel Boring Machines (TBMs) - similar to the ones deployed for digging the underground sections of Mumbai Metro projects - to cause minimum disturbances to wildlife in the 87-square km SGNP.

The first inter-district road tunnel project in the state, it will entail acquiring 16.54 hectares private and 40.46 hectare of SGNP lands and will connect Borivali WEH in Mumbai with the Tikuji-ni-Wadi on the Thane side.

The project will have cross-tunnels every 300 metres, drainage systems, smoke detector, and jet fand to keep the air clean and fresh, will result in fuel savings of over a million lakh tonnes and reduce emissions by 36 per cent, the minister said.