Aqua Line (Mumbai Metro)
Aqua Line (Line 3) is a rapid transit metro line of the Mumbai Metro in the city of Mumbai, Maharashtra, India. The 33.5 km (20.82 mi) route is Mumbai Metro's first underground line with 27 stations, 26 of which are underground stations and one is at-grade. The line will run from Navy Nagar in the far-south of Mumbai to Aarey Depot in the north-centre, and will include connections to other metro lines, monorail, suburban rail, inter-city rail, and Mumbai's International Airport. Aqua Line is expected to reduce road congestion as well as the load on the Western Line between Bandra and Churchgate.
The project is being implemented, and will be operated, by the Mumbai Metro Rail Corporation Limited (MMRCL). The total cost of this line is estimated at ₹30,000 crore (US$3.5 billion). The project is being funded by five major groups: MMRCL, Padeco, MMRDA, CREC, and JICA; the last of which provided a soft loan of ₹13,235 crore (US$1.6 billion).
The section of the line between Bandra Kurla Complex and Dharavi stations includes a 170-metre (560 ft) long twin-tunnel passing under the Mithi river. One of the tunnels was completed in March 2020. This is the second under-river metro rail tunnel in India after the tunnel underneath the Hooghly river on Kolkata Metro Green Line. The first phase of the project was inaugurated on 5 October 2024 by Prime Minister Narendra Modi. The ₹14,120 crore BKC to Aarey Jogeshwari-Vikhroli Link Road section of the line. The underground metro line is 33.5 km (20.82 mi) long, but only a part of it, a 12.44 km (7.73 mi) stretch, has been completed. It is also called the Colaba-Bandra-Seepz line. The corridor consists of 10 stations. In a major push to boost urban mobility in the region, Prime Minister Modi flagged off a metro service scheduled to run from BKC to Aarey JVLR in the western part of Mumbai. He also took a ride on the metro between BKC and Santacruz stations. Phase 2A of the line stretching from BKC to Acharya Atre Chowk, covering an additional five stations, was inaugurated on 9 May 2025, under the hands of CM Devendra Fadnavis and other officials present.
The construction of this metro route faced hurdles from environmentalists and activists lodging numerous PILs over cutting of trees in various region accompanied with a larger protest in Aarey over the carshed construction. PILs were either dismissed or did not succeed, as both the Supreme Court and the Bombay High Court cited the importance of the metro project.