Aqua Line (Mumbai Metro)
The 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 in Mumbai Metro's first underground line with 27 stations, 26 of which are underground stations and one is at-grade. It is the first metro line to be fully underground in Mumbai. The line runs from Cuffe Parade in the far south of Mumbai to Aarey JVLR in the north centre, and includes connections to other metro lines, monorail, suburban rail, inter-city rail, and Mumbai's International Airport. The Aqua Line is expected to reduce road congestion as well as the load on the Western Line between Bandra and Churchgate.
The project was implemented is 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 was funded by five major groups: MMRCL, Padeco, MMRDA, 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. This is the second under-river metro rail tunnel in India after the first 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, which consists of 10 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 final 10.99 km stretch of the line from Acharya Atre Chowk to Cuffe Parade was inaugurated by Modi, along with the Navi Mumbai International Airport on 8 October 2025.
The construction of this metro route faced hurdles from environmentalists and activists lodging numerous PILs over cutting of trees in various regions 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.