For a buyer, that means the tunnel should not be in your price today. This page sets out the route, the money, the legal and technical hurdles, the separate Hebbal short tunnel that is under way, and the realistic effect on homes near each end.

What is the Bengaluru tunnel road and where does it run?

Officially the North-South underground corridor, it is a twin-tube road tunnel under central Bengaluru, taken up by Bengaluru Smart Infrastructure Ltd (B-SMILE). The state Cabinet approved the 16.74 km twin tube on 22 May 2025, as The Week reported. It is part of a wider plan for two underground roads totalling about 40 km and 13 flyovers and elevated corridors.

When the corporation first proposed it in June 2024, the planned entry and exit points were the KSRP quarters at Central Silk Board, Lalbagh, Bangalore Golf Club, Palace Grounds and government land next to Esteem Mall near the Hebbal flyover.

The detailed project report later identified five shaft locations for the tunnel boring machines: Lalbagh, a private property of St John's Medical College Hospital on Hosur Road, Palace Grounds near Mekhri Circle, the Race Course behind Freedom Park, and a seven-acre KIADB plot in Hebbal. It also planned a two-lane entry to the tunnel from Ashoka Pillar Circle and an exit ramp before Marigowda Junction on Siddapura Road.

Tunnel road project status: the latest dated events

  • 22 December 2025: financial bids opened. Adani Group was lowest for both packages at ₹22,267 crore, about 24% and 28% above the estimates for the two packages. Only two bidders reached the financial round.
  • 24 August 2026: The Hans India reported the contract was still unawarded and that the Cabinet must decide whether to accept the bid, negotiate it down or retender.
  • 4 September 2026: the Karnataka High Court asked the authorities to place the Geological Survey of India's report on Lalbagh's Peninsular Gneiss rock before it, and sought an engineer's presentation on the Hebbal Lake short tunnel.
  • 5 and 6 September 2026: the GSI expert committee's 27-page report was reported to warn that tunnelling and excavation near the Lalbagh rock could cause small displacements or cracks, and that the nearby Kempegowda watchtower amplifies the concern. It recommended an independent review of the location of TBM Shaft 4.
  • 11 September 2026: at a GBA meeting the Chief Minister asked officials to find land other than Lalbagh for the boring shaft. A shaft needs at least five contiguous acres, which is hard to find on this corridor.
  • Pending in court: citizen groups have challenged the project in the High Court, including for the lack of an environmental impact assessment and of land transport authority approval. Petitions were also filed before the National Green Tribunal in 2025.

How much will the tunnel road toll be?

The detailed project report by Rodic Consultants recommended ₹19 per km, up from ₹16 in the feasibility report six months earlier. On 16.75 km that is up to about ₹318 one way. The report justified the rate partly because the tunnel was expected to open only in 2029 to 2030. Two-wheelers and auto-rickshaws are expected to be barred, according to secondary reports of the DPR.

The toll has not been fixed by any concession agreement, because there is no concession yet. The rate can change.

  • Worked example, one car commuting daily end to end: 16.75 km × ₹19 = ₹318.25 one way.
  • Round trip: ₹318.25 × 2 = ₹636.50.
  • 22 working days a month: ₹636.50 × 22 = ₹14,003 a month.
  • A year: ₹14,003 × 12 = about ₹1.68 lakh. That is a household running cost, so judge any tunnel premium on a home against it.

How much does it cost and who pays?

  • Cabinet cost: ₹17,780 crore, under a modified build-own-operate-transfer model, with the government paying 40% and the concessionaire 60% (Deccan Herald, June 2025).
  • B-SMILE estimate at bidding: ₹17,698 crore. Lowest bid: ₹22,267 crore, about ₹4,569 crore higher.
  • Bidders and model: four firms bid; two reached the financial round. The tender is on a build-operate-transfer basis, according to Deccan Herald.
  • Overlap with metro: the 37.8 km Sarjapur to Hebbal metro line proposed under Phase 3A runs along much of the same north-south corridor, which limits how far the tunnel can be re-routed.

The Hebbal short tunnel is a separate project

Buyers often confuse the two. The Hebbal short tunnel is a ₹1,140 crore, roughly 2.3 km three-lane underpass meant to decongest the Airport Road junction. The Bangalore Development Authority awarded it in June 2026 after the Cabinet cleared it, and groundwork began on Ballari Road and inside the veterinary university campus by early August.

It has its own objections. On 21 September 2026 the GBA tree officer invited objections to felling 1,128 trees along it, and about 3.5 acres of Hebbal Lake land are involved. Deccan Herald reported on 27 September that a citizens' delegation had given the environment minister a petition with over 21,000 signatures seeking an environmental assessment. The High Court has asked for a presentation on its effect on the lake's water flow.

When will the tunnel road be completed?

No official completion date exists, because no contract has been signed. The DPR assumed operation in 2029 to 2030, and the tender reportedly set a three-year build. Add the time needed to settle the alignment, award the contract and clear the court cases, and a realistic opening is well after 2030. Buyers should treat the main tunnel as uncertain, not delayed.

What the tunnel road means for property near each end

Asking prices below are Square Yards figures for apartments, June 2026 quarter, read on 17 October 2026. None of these markets is priced on the tunnel today, and that is the right way to keep it.

  • Hebbal (north portal near Esteem Mall): about ₹17,100 per sq ft. Hebbal's value rests on the airport road, Manyata and the coming Blue Line, not on the tunnel. See Hebbal, Bangalore and projects such as Prestige Fairfield Hebbal.
  • Mekhri Circle and Palace Grounds: homes here could gain a fast run south if a ramp is built nearby, but they also face years of shaft work. A project in this pocket: Four Seasons Private Residences At Embassy One Embassy One Bellary Road Near Mekhri Circle. Read Sadashivanagar, Bengaluru: Buyer's Guide 2026 — Luxury Homes, Prices and What to Know for the area.
  • Lalbagh and Richmond Town belt: Richmond Town about ₹21,500 per sq ft. This is where the alignment is now in doubt.
  • Silk Board end (south portal at the KSRP quarters): HSR Layout about ₹17,638 per sq ft (headline), BTM Layout about ₹13,850. This end already has the Yellow Line and will get the Blue Line, which matter far more.
  • Homes within a few hundred metres of a ramp or shaft carry construction risk and, later, traffic at the portal. Homes a little further away get the access without the noise.

A buyer's checklist on tunnel road claims

  • If a seller cites the tunnel, ask which ramp is nearest and whether that ramp survives the alignment review.
  • Do not pay extra for a tolled road that has no contract, no fixed toll and no date.
  • Check the metro instead: the Yellow Line runs today, the Blue Line is targeted for 2027, and the Red Line is a longer-term plan. See Red Line Metro Bangalore: Hebbal–Sarjapur Stations and 2033 Date.
  • Read How Infrastructure Projects Affect Property Prices for how prices usually move at announcement, construction and opening.
  • Track three triggers: a Cabinet decision on the bid, a published revised alignment, and the High Court's orders.