Phase II The construction of the first phase of
Chennai Metro started in June 2009. Commercial operations started on the
green line in June 2015. On 10 February 2019, the extension of
blue line was opened, completing the first phase of the metro. In July 2016,
Government of Tamil Nadu announced that the second phase would have three lines totaling in length with 104 stations. Two corridors would extend from connecting with
Siruseri and respectively with the third corridor connecting
Koyambedu with
Lighthouse. In July 2017, the state government announced an extension in Phase II, involving an extension of line four from
Lighthouse up to
Poonamallee with an intersection with the
Madhavaram–Sholinganallur line at
Alwarthirunagar. The line will extend to with
elevated and
underground. It will consist of 30 stations including 12 undergrounds stations. The stations for the second phase were designed to be smaller than the existing stations operational in the first phase. On 20 November 2020, foundation stone for the second phase was laid and construction commenced. In November 2022, Alstom was awarded the contract to supply metro coaches for the phase II expansion. In May 2023, CMRL announced a revised plan for the second phase. As per the plan, the line will extend for with 27 stations. The second phase is estimated to cost of which initially was loaned by
Japan International Cooperation Agency. On 14 February 2021, the
Prime Minister of India announced that the government has set aside for the construction of phase II and further extension. In January 2025, Chennai Metro announced that the operations on to stretch will start in February 2026, with no intermediate stoppages at stations from Alapakkam to Saligramam. But Now Possibility Start in June 2026
Phase II extension In 2022, the state government proposed an extension plan for the fourth line from Poonamalee to
Parandur, covering an approximate . Detailed Project Report (DPR) of the line was prepared and submitted to
Government of Tamil Nadu which approved the line in June 2025. This extension would be implemented in 2 phases, from to Sunguvarchatram in first phase and then to Parandur in second phase. The DPR is currently forwarded to
Government of India for final approval. Another extension of the corridor eastward from
Lighthouse to
High Court is also being planned. == Stations ==