Huge 'twin tunnels' in £1.2bn project to end traffic jams in one of world's biggest cities

An aerial view of construction of new highway (Image: The Maharashtra Index X social media)

India is investing more than one billion pounds in building a new coastal road, aimed at easing congestions in one of its biggest cities.

The Coastal Road Project is a 22km high-speed corridor along Mumbai's western coastline connecting Marine Lines in the south to Kandivali in the north.

The new highway is expected to drastically reduce travel times between South Mumbai and the Western Suburbs from two hours to just 40 minutes. 

Officials estimate that as many as 130,000 vehicles a day will use the eight-lane high-speed corridor once it is fully completed.

The cost of the project is expected to come to around US$1.6 billion (£1.2bn), according to various reports.

An artist's impression of completed tunnel (Image: India Infra Story Book X social media)

The first phase of the project was inaugurated on 11 March 2024 and consists of an 11km (7 miles) section from Princess Street flyover to the Worli end of the Bandra–Worli Sea Link.

As part of the second phase, a four-kilometre-long twin tunnel is planned to be built.

The tunnel will be constructed at a depth of 40 metres below ground and will pass under rivers, creeks and mangrove patches.

It will connect Mindspace in Malad with Charkop Gaon, Kandivali, in the western suburbs of Mumbai.

The tunnels will each have three lanes and have a width of between 36 and 45 metres.

Additionally, they will be separated by a distance of around 15.1 metres, according to the design plans.

Abhijit Bangar, a municipal commissioner overseeing the project told the Indian Express: “The northern and southern end of the tunnels originate from Charkop and Mindspace (Malad), the two tunnels will run parallel to each other and will be part of the packages C and D of the phase two of MCRP, which is divided into six packages.

"Considering the tunnels will pass below mangrove patches, rivers and creeks, we can say that this will be Mumbai’s first vehicular tunnels that will pass underneath water bodies.

"Earlier, it was proposed that the twin tunnels of the Goregaon Mulund Link Road (GMLR) would pass below the Vihar and Tulsi lakes of Mumbai, however, their alignment was later changed.” 

The project is not without its controversies and has attracted opposition from various environmental groups.

Critics claimed that construction work has negatively impacted tidal water flows, resulting in the destruction of thousands of hectares of paddy fields.