Hebbal to Silk Board Tunnel Road: Status, Cost and Buyer Checks (October 2026)

The Hebbal to Silk Board tunnel road is a proposed 16.75 km underground road across Bangalore from north to south. Bids are in, the lowest one is well above the state's estimate, and the contract was still awaiting a decision at the start of October 2026. This guide sets out the plan, the money, the open questions and the way a home buyer should treat a "near the tunnel road" claim.

The Plan in Brief

The road is designed as a pair of tunnels, each carrying three lanes in one direction. It starts at Esteem Mall junction in Hebbal and ends at Central Silk Board junction. The state's project company, Bengaluru Smart Infrastructure Limited (B-SMILE), is the agency in charge.

The main facts are these:

• Length: 16.75 km, split into two packages of about equal length
• Package 1: Esteem Mall junction to the Seshadri Road and Race Course Road junction
• Package 2: Seshadri Road to Central Silk Board junction
• State estimate: Rs. 17,698 crore (Rs. 8,770 crore and Rs. 8,928 crore for the two packages)
• Construction period in the tender: 50 months from the award

The tunnel is for motor vehicles and will be tolled. It is a different project from the short tunnel at Hebbal junction towards Mekhri Circle, whose foundation stone was laid in June 2026.

From Approval to Bids

The Karnataka cabinet approved the north-south tunnel in May 2025 and chose a model in which a private company builds, operates and later hands back the road. The state is to fund up to 40% of the construction cost. The company raises the rest and recovers it from tolls over a 30-year concession.

B-SMILE floated the tender in July 2025, and four firms had bid by the extended closing date in November 2025. Two of them cleared the technical round. When the price bids were opened in December 2025, the Adani Group was the lowest bidder for both packages.

Why the Contract Is Still Pending

The lowest bid totals Rs. 22,267 crore against the estimate of Rs. 17,698 crore, a gap of about Rs. 4,569 crore. It is about 24% above the estimate on Package 1 and about 28% above on Package 2. A bid that far above the estimate needs the cabinet's approval, so B-SMILE sent the file to the state government on 29 May 2026.

The state has three courses open: negotiate the price down with the lowest bidder, revise its own estimate, or cancel the tender and call fresh bids. A decision was still awaited at the start of October 2026. Until it comes, the tunnel has neither a contractor nor a start date.

The Lalbagh question

The approved design needs land at Lalbagh: about six acres during construction and about one acre for good. Citizens' groups have objected to this. On 3 September 2026 the cabinet withdrew a Bill that would have allowed a small share of park land to be used for public projects.

On 9 September 2026 the Chief Minister said he had asked for a study of alternatives to the Lalbagh land. A change there could alter the route in the southern half and the position of the ramps. The alignment is therefore best treated as open, along with the cost.

What the Tunnel Would and Would Not Do

The stated aim is to cut the Hebbal to Silk Board drive from 90 minutes or more at peak hours to about 35 minutes. That gain would go to people who drive and are willing to pay the toll. The toll rates are to be fixed after the contract is awarded.

A tunnel differs from a metro line in one way that matters to property. A metro station brings footfall, shops and a walkable catchment around it. A tunnel passes under a neighbourhood without stopping, and only the areas near its entry and exit ramps gain direct access.

Several limits follow from that:

• A home above the tunnel route gains little unless a ramp is close by
• Ramp locations can bring more surface traffic to the roads around them
• Bus and metro users gain only if surface roads clear up as a result
• Four years or more of digging near the ramps means dust, noise and diversions for nearby residents

Localities Along the Route

The northern end is at Hebbal, where Bellary Road meets the Outer Ring Road. The area already has the airport road and the flyover, and the Blue Line metro is under construction there. Homes at this end have a case that does not depend on the tunnel.

The middle of the route passes under the Mekhri Circle, Palace Grounds and Race Course Road area and then the city centre. This stretch would see the most construction activity around the intermediate ramps. It is also the stretch most affected if the route near Lalbagh changes.

The southern end is at Silk Board, beside HSR Layout and Koramangala. The Yellow Line metro already runs through Silk Board, and the Blue Line will start there. A buyer at this end can weigh working transport today against a tunnel that is still a proposal.

How Buyers Should Treat a Tunnel Claim

A project at the bid stage should carry little weight in the price paid for a home today. The tender gives 50 months for construction, so even an award in late 2026 would place the opening after 2030. Large tunnelling jobs in Indian cities have often taken longer than first planned.

These checks keep the tunnel in its proper place in a purchase:

• Ask whether the contract has been awarded and whether the final route has been notified
• Find the nearest entry or exit ramp on the notified route and measure the drive to it
• Set the quoted price against similar homes nearby that are sold without the tunnel claim
• Count the toll as a daily cost when working out the benefit
• Test the present commute at peak hours, by road and by metro
• Allow for several years of construction if the home is close to a ramp site
• Verify the RERA registration, title and khata of the project, which matter more than any proposed road

The sound order is to choose a home that works on the roads and metro lines in use now. If the tunnel is built, it arrives as a gain. Our team is glad to explain what is open, under construction or only proposed near any project in North Bangalore or along the route.