Mumbai's metro network is set to expand significantly in 2026 with portions of four lines and one extension slated for inauguration. Key openings include Phase 1 of Line 9, extending connectivity to Mira Bhayandar, and sections of Line 2B serving eastern suburbs like Chembur. Lines 4 and 4A, linking Mumbai and Thane, are also expected to partially open. These developments follow the 2025 inauguration of the Aqua Line and aim to enhance public transport options across the Mumbai Metropolitan Region.