Namma Metro Red Line: Cabinet Clears Sarjapur-Hebbal Corridor

Bengaluru's public transport map is about to get a major addition. The Karnataka Cabinet on Friday, December 6, approved Phase 3A of the Bengaluru Metro's Red Line, which will connect Sarjapur in southeastern Bengaluru with Hebbal in the north. The project proposal, estimated to cost Rs 28,405 crore, will now be forwarded to the Union Cabinet for approval, as the Union government holds a 50% equity stake in Namma Metro.

The corridor has been years in the making. The Sarjapur-Hebbal Metro line, first announced by Chief Minister Siddaramaiah in his budget speech on 7 July, 2023, was initially projected to cost Rs 16,000 crore. In June 2024, the Bangalore Metro Rail Corporation Limited (BMRCL) submitted a detailed project report (DPR) for the 37-km Hebbal-Sarjapur corridor to the State government, and by the time it reached the Cabinet, design adjustments and expanded infrastructure needs had pushed the cost up.

Once fully built, the 36.59-km line will have 17 elevated and 11 underground stations, and four interchanges: Iblur on the Outer Ring Road (with Blue Line), Dairy Circle on Bannerghatta Road (Pink Line), KR Circle (Purple Line) and Hebbal (Blue and Orange lines). The route will run elevated along Sarjapura Road and Outer Ring Road before going underground from Koramangala, passing key junctions including Dairy Circle, Nimhans, KR Circle and Palace Road, before turning elevated again near Ganganagar and continuing along Ballari Road to Hebbal. Once completed, the corridor is projected to handle over 6.4 lakh daily passengers, linking Sarjapur's IT hub with HSR Layout, Koramangala, the central business district and Hebbal.

The project's high cost drew scrutiny from the Centre. At Rs 28,405 crore, or Rs 776.3 crore per km, it was the most expensive corridor in Namma Metro's history, and concerns over this cost put the project on hold at the central approval stage. Following the Centre's directive, BMRCL appointed global consultancy Systra to review and optimise the DPR. Systra's review reduced the underground station lengths by 40 metres without changing the route or station count, bringing the cost down to Rs 25,485 crore — a saving of Rs 2,920 crore — with the cost per km dropping from Rs 767 crore to Rs 688 crore.

The revised numbers have kept the project moving, even as a parallel proposal for a tunnel road between Silk Board and Hebbal raised fears the metro could be sidelined. Systra submitted its report in late 2025, leading to further revisions in February 2026, and an updated DPR was resubmitted to the Centre in April 2026, with union approval now expected around October 2026. Geotechnical surveys for the corridor already began in January 2026 as preliminary ground work. Full construction is expected to begin only after Union Cabinet clearance, with an operational target now pushed out to around 2033.

For homebuyers, the Red Line's significance lies in the neighbourhoods it stitches together. The corridor runs through some of Bengaluru's most active residential and rental markets — Sarjapur Road, Bellandur, Koramangala, and the Hebbal-Ballari Road belt in the north — all areas where large-format townships and premium apartment developments have been coming up steadily over the past few years. A confirmed metro alignment, even in the pre-construction stage, tends to firm up buyer sentiment and rental demand in the micro-markets it touches, particularly along stretches like Sarjapur Road that currently rely heavily on road-based commutes to the ORR IT corridor.

While the timeline for an operational Red Line stretches out toward the early 2030s, the Cabinet's approval and the subsequent cost rationalisation mark real, tangible progress on a project that has been discussed since Bengaluru's Comprehensive Mobility Plan 2020. For buyers evaluating homes along the Sarjapur-Koramangala-Hebbal axis, this is a corridor worth watching closely over the next few Union Cabinet review cycles.