Few Bengaluru projects have produced as many headlines, or as much confusion, as the Hebbal to Silk Board tunnel road. Brochures along Bellary Road, Jayamahal and Hosur Road already mention it, and I am regularly asked whether a flat near one of the proposed ramps is worth paying more for.

This post sets out where the project actually stands as of 24 September 2026, what has been reported about its route and cost, and how I suggest buyers and owners along the corridor think about it. The short version: it is a serious proposal with real money behind the bids, but it is not yet a project you can price into a home.

What the tunnel road is

The project is a twin-tube underground road running north to south between the Hebbal junction (near Esteem Mall) and Central Silk Board. Recent reports put the length at 16.75 km. Earlier versions were larger: a June 2024 proposal from the then BBMP described an 18 km road, and some September 2026 reports still quote figures between 16.7 and 17.5 km. The difference mainly reflects how ramps and approach sections are counted.

The detailed plan reported by Deccan Herald in June 2025 described three-lane tunnels in each direction, two-lane entry and exit ramps, eight tunnel boring machines and roughly 33.5 km of tunnelling in total, with a three-year construction target. The project is being run by B-SMILE, the special purpose vehicle set up for Bengaluru's large road projects, now under the Greater Bengaluru Authority.

The financing model is build-operate-transfer. The government is to provide 40% as viability gap funding and the private concessionaire 60%, recovering its money through tolls over a reported 30-year concession.

Key facts at a glance

Where the bids and approvals stand

Four companies submitted technical bids in late 2025. According to Deccan Herald (22 December 2025), only Adani Group and Vishwa Samudra Engineering reached the financial round. Dilip Buildcon was disqualified, and RVNL's joint venture partner did not meet technical requirements.

Adani was the lowest bidder on both packages, at ₹22,267 crore in total. That is roughly ₹4,600 crore above the estimate. Because the gap is so large, the tender needs the state Cabinet's approval, and the Cabinet can accept the bid, negotiate it down, or retender.

Through the middle of 2026 that decision kept being reported as pending. The Hans India reported on 24 August 2026 that the contract remained unawarded, while noting that Adani had begun preliminary soil and geotechnical investigation along the route. As of the date of this post I have found no report of a letter of award or a signed concession agreement.

The High Court cases and the Lalbagh question

Several public interest petitions challenge the project, arguing that the tender went ahead without a proper environmental impact assessment and other statutory steps. On 16 July 2026, LiveLaw reported that a Division Bench of the Karnataka High Court directed that any contract would be subject to the outcome of the petitions, and that no equities should be created while they are pending. In September the court also asked for the Geological Survey of India's report on the Peninsular Gneiss rock at Lalbagh.

Lalbagh became the flashpoint. The plan needed about six acres of the garden temporarily and one acre permanently for ramps. The GSI flagged risks to the ancient rock formation and to groundwater. A Parks (Preservation) Amendment Bill that would have allowed up to 5% of park land to be used for infrastructure drew strong protests, and the Cabinet withdrew it on 3 September 2026.

On 9 September, Chief Minister D K Shivakumar said alternatives to Lalbagh land were being studied. News Karnataka reported on 12 September that Forest Minister Ramalinga Reddy confirmed Lalbagh land would not be used, and that options being examined include NIMHANS land, cemetery land near Wilson Garden, or a route beneath Lalbagh Road. No new alignment had been announced by 24 September.

A separate, shorter tunnel at Hebbal

Do not confuse the main project with the 2.2 km Hebbal tunnel from the Hebbal flyover junction to the Veterinary College through GKVK, costing about ₹1,385 crore. Mongabay India reported that groundwork began in early August 2026, that it intrudes into the Hebbal Lake buffer zone, and that it is also before the High Court. If you live near Hebbal, this is the construction you are more likely to feel first.

What it means for property along the route

A completed tunnel would mostly help through traffic: someone driving from north Bengaluru to Koramangala, HSR or Electronic City who wants to skip the central city. It is a tolled, limited-access road, so the benefit is concentrated near the ramps, and it carries cars rather than people on foot or by bus.

Hebbal

Hebbal's value already rests on the airport road, the Outer Ring Road, existing offices and the planned metro interchange. The northern portal and the shorter Hebbal tunnel mean years of excavation, diversions and dust near the flyover. For homes close to Esteem Mall and the lake edge, the near-term effect is more likely to be disruption than uplift. My north Bangalore airport corridor guide covers the broader drivers.

Mekhri Circle and Palace Grounds

This is the central distribution point in the plan, and it involves defence land around Mekhri Circle that still needs clearance. Sadashivanagar, RMV Extension and Jayamahal are established, low-supply neighbourhoods whose prices depend on location, schools and plot sizes, not on a ramp. I would not expect a premium here, and I would check exactly where any ramp is planned before buying a home facing one.

Lalbagh, Wilson Garden and the southern central areas

This is the stretch where the route is now genuinely undecided. If ramps move to NIMHANS land, Wilson Garden or Lalbagh Road, the streets that see construction traffic could change. Until a revised alignment is published, any claim that a particular building is "next to the tunnel exit" is guesswork.

Silk Board and Hosur Road

The southern portal is planned at the KSRP quarters near Silk Board, one of the city's worst junctions. BTM Layout, HSR and Madiwala residents would gain most if the tunnel works as intended, but they also face the longest construction period at a junction that is already strained.

Why you should not pay a premium for unbuilt infrastructure

I give clients the same advice for every announced project: pay for what exists, and treat the rest as an option you get for free. With this tunnel road, the reasons are unusually clear.

• No contractor yet. The bid is about 26% above estimate and needs Cabinet approval. Retendering is a real possibility.
• Route not final. The southern ramps are being redesigned, and defence land is still under discussion in the north.
• Court risk. The High Court has said contracts are subject to the PILs.
• Toll unknown. An estimated ₹300 or more each way would limit everyday use.
• Long timeline. Even if work started in 2027, a three-year tunnelling target on Bengaluru rock would put opening around 2030 at the earliest, and large tunnels often run late.
• Disruption comes first. Owners near portals carry years of construction before any benefit.

If a seller or developer is pricing in the tunnel, ask what the price would be without it, and compare it with recent registered sales nearby. Add the full buying cost too: stamp duty, registration and, for under-construction homes, GST. The Proptals cost calculator gives an all-in figure.

How to weigh it against the metro

Metro lines change daily life for far more households than a tolled car tunnel, because they serve walkers, students, older people and anyone without a car.

When comparing two homes, give more weight to a metro station that is operating or under active construction within walking distance than to a proposed tunnel ramp. Deccan Herald has also noted possible conflicts between the tunnel alignment and Metro Phase 3A, so the two projects are not independent. For station-level detail, see my Metro Phase 3 property map.

Other 2026 road projects worth knowing

The Bengaluru Business Corridor, the renamed Peripheral Ring Road, is further along than the tunnel. It is a roughly 74 km ring, and in June 2026 Deccan Herald reported that Shankara Narayana Constructions received the letter of acceptance for Package 1 (from Madavara on Tumakuru Road towards Ballari Road) at ₹3,348 crore, including ten years of maintenance. Land acquisition across the full ring is still uneven. If you own land near the alignment, the compensation route matters more than headlines, and that is worth discussing with a lawyer.

A checklist for buyers and owners on the corridor

1. Price the home on today's access, metro and recent registered sales, not on the tunnel.
2. Ask the seller or developer for the source of any "tunnel exit" claim, and check it against the latest official alignment.
3. If you are near Hebbal, Mekhri Circle, Lalbagh Road or Silk Board, plan for three to four years of possible construction nearby.
4. Landlords near portals should expect some tenants to leave during heavy works and price renewals realistically.
5. Owners thinking of selling should not wait for the tunnel to "arrive". Sell on your own timeline.
6. Watch for four things: the Cabinet decision on the bid, a published revised alignment, the High Court's ruling on the PILs, and a notified toll.

Frequently Asked Questions

Has the Hebbal to Silk Board tunnel road been awarded to Adani?

Not as of 24 September 2026. Adani Group was the lowest bidder at ₹22,267 crore, but the bid is well above the ₹17,698 crore estimate and needs a state Cabinet decision before any award.

How long is the tunnel road and where are the exits?

Recent reports put it at about 16.75 km. Proposed entry and exit points include Hebbal near Esteem Mall, Palace Grounds or Mekhri Circle, the Race Course area, Lalbagh and Silk Board, but the southern ramps are being redesigned to avoid Lalbagh land.

When will the tunnel road open?

There is no official opening date. The plan assumes about three years of construction after work starts, and work cannot start until the contract is awarded, so any date before 2030 should be treated with caution.

Will it raise property prices near Hebbal or Silk Board?

Nobody can say with certainty. Near-term construction is likely to cause disruption around the portals, and any benefit depends on the final route, toll and completion, so I advise against paying a premium for it today.

Is the project facing court cases?

Yes. The Karnataka High Court is hearing public interest petitions challenging the tender, and in July 2026 it directed that any contract would be subject to the outcome of those petitions.

If you are buying, selling or holding property near Hebbal, Mekhri Circle, Lalbagh or Silk Board and want a realistic view of what it is worth today, tell me what you are looking for on Post Your Requirement or see how we help owners on Sell Your Home. Message me on WhatsApp

Sources

• Deccan Herald: Adani Group lowest bidder for both packages of Bengaluru tunnel road project
• The Hans India: Adani Enterprises emerges L1, contract still pending
• LiveLaw: Bengaluru twin tunnel contracts will be subject to outcome of PILs, says Karnataka High Court
• The News Minute: Karnataka CM Shivakumar hints at new tunnel road alignment to avoid Lalbagh
• News Karnataka: Bengaluru tunnel road to bypass Lalbagh amid protests
• Deccan Herald: 8 TBMs, 3-year deadline for 16.75 km Hebbal-Silk Board tunnel
• Deccan Herald: SNC wins Rs 3,348 crore deal to build first leg of Bengaluru Business Corridor project

Last updated Sep 24, 2026. Figures and rules change; check current details with a professional before you act.

ABOUT THE AUTHOR

Tariq Sallam

Founder, Proptals · Karnataka RERA registered agent

Tariq has advised buyers, sellers, landlords, landowners and developers in Bangalore since 2004. He writes about what he sees on site visits, in negotiations and at registration offices.

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