Chennai Metro Phase 3 is a proposed network of about 65 km that has not yet been approved by the Centre. On 11 October 2026, at the inauguration of Phase 2's first stretch, Chief Minister C Joseph Vijay asked Prime Minister Narendra Modi for early approval of Phase 3, naming Airport–Kilambakkam and Poonamallee–Sunguvarchatram, and asked that Koyambedu–Pattabiram be included and cleared quickly (ThePrint/PTI; DT Next). The state had already asked the Centre to approve all three in its 2026-27 Budget (Swarajya, 5 August 2026).

Updated 15 October 2026. The page that ranks first for this search is a 2024 news report on the Phase 2 approval, which does not cover Phase 3 at all; the second, DT Next's report of 11 October, has no lengths, costs or stations. Below we set out each corridor from the reports we read, how far each has moved, and what that means for a home buyer.

Where Phase 2 stands

Phase 3 builds on Phase 2. The Union Cabinet approved Phase 2's three corridors in October 2024: 118.9 km with 128 stations at a completion cost of ₹63,246 crore, giving a 173 km network once operational (The Week/PTI, 3 October 2024). On 11 October 2026, the 14.64 km Corridor 4 stretch between Poonamallee Bypass and Vadapalani opened, and the Chief Minister said another 104 km was under construction (DT Next). Our status page on every Phase 2 corridor: Chennai Metro Phase 2 Opening Date: Every Corridor's Status, 2026

The three Phase 3 corridors at a glance

  • Airport–Kilambakkam: 15.46 km, 13 elevated stations, about ₹9,335 crore including an elevated road (Swarajya, 22 March 2026; Angel One, 25 July 2026).
  • Koyambedu–Pattabiram: 21.76 km along the Outer Ring Road, 19 stations, ₹9,928.33 crore at 2025 prices (Swarajya, 5 May 2025).
  • Poonamallee–Sunguvarchatram: 27.9 km, 14 elevated stations, ₹8,779 crore (Swarajya, 27 August 2026).
  • Together these come to about 65 km, matching the figure given on 11 October. All three were approved by the state and are awaiting the Centre.

Airport to Kilambakkam

This extends the Blue Line south from Chennai Airport to the Kalaignar Centenary Bus Terminus at Kilambakkam, through Pallavaram, Chromepet, Tambaram, Perungalathur and Vandalur. It is designed as a double-decker: the metro on the upper level and a four-lane elevated road below to ease congestion on GST Road, with ramps near Tambaram to the Outer Ring Road (Swarajya; Angel One). Swarajya put the expected ridership benefit at about 15 lakh commuters.

Koyambedu to Pattabiram

First planned as a 16 km Koyambedu–Avadi link, the corridor was lengthened to Pattabiram after feasibility and DPR studies. It runs along the Outer Ring Road through the western industrial and residential belt.

Poonamallee to Sunguvarchatram

This was the first phase of a longer corridor to the proposed Parandur airport. After the state decided to drop the Parandur greenfield airport, CMRL said it would continue with the Poonamallee–Sunguvarchatram section on the strength of demand in the western suburbs and the industrial belt around Sriperumbudur (Swarajya, 27 August 2026). Any extension beyond Sunguvarchatram would be examined later, depending on traffic.

How to track the approval

Swarajya's March 2026 report on the RTI reply describes the steps a metro proposal passes through at the Centre, and it is a useful checklist for anyone waiting on Phase 3:

  • State approval and DPR sent to the Union Housing and Urban Affairs Ministry: done for all three corridors, per the reports above.
  • Preliminary examination at the ministry: where the Airport–Kilambakkam DPR stood in March 2026.
  • Public Investment Board appraisal: the RTI reply said the proposal had not reached this stage.
  • Cabinet Committee on Economic Affairs or Union Cabinet approval: the sanction that releases central funding, as happened for Phase 2 in October 2024.
  • Tenders and civil contracts: the point at which a construction timeline becomes meaningful.
  • Until a corridor reaches the last two steps, read any 'Phase 3 is coming' claim in a sales pitch as a hope, not a plan.

When could Phase 3 open?

No report we read gives a construction start or completion date for any Phase 3 corridor, and none has been sanctioned by the Centre. For scale, Phase 2 was approved in October 2024 with a planned completion of 2027 (The Week), and its first 14.64 km opened in October 2026 with 104 km still under construction. A buyer should treat Phase 3 as a long-term possibility, not a dated benefit.

What this means if you are buying in Chennai

  • Buy for what runs today. Value the transport, roads and jobs a locality already has, and treat a Phase 3 station as upside.
  • Watch for the Centre's sanction. Approval, then contracts, are the milestones that matter; until then the alignment and station spots can change, as the move from Avadi to Pattabiram showed.
  • Do not pay a premium for a station name in a brochure. Ask for the distance to a station on the published alignment, and check it yourself.
  • Expect construction years on GST Road and the ORR if the corridors are approved; the elevated road on the Airport–Kilambakkam line would add to that.
  • Our evidence on how metro lines move prices: Does a Metro Really Raise Property Prices? The Evidence, and the Bengaluru Caveats

Other lines in the same request

On 11 October the Chief Minister also sought early sanction of an interstate metro from Hosur to Bommasandra in Karnataka and asked the Centre to reconsider metro projects for Coimbatore and Madurai (ThePrint/PTI). None of these is part of Chennai's Phase 3.