The Tamil Nadu Government has approved the construction of Phase 2's Line 4 Extension of the Chennai Metro, spanning 52.94 km and connecting Poonamallee, Sunguvarchatram, and Parandur. The estimated project cost is ₹15,906 crore. The government has also approved the first phase of this corridor’s implementation, covering 27.9 km from Poonamallee to Sunguvarchatram.