}
Line 4 In June 2015, the
Mumbai Metropolitan Region Development Authority (MMRDA) proposed building a Wadala-Thane-Kasarvadavali metro line as part of a plan to build six new metro lines at a total estimated cost of . Line 4 was approved in June 2016, and was estimated to cost . The foundation stone for Metro 4 was laid by Prime Minister Narendra Modi on 24 December 2016. The Maharashtra Coastal Zone Management Authority granted
Coastal Regulation Zone (CRZ) clearance to the project in February 2017. Over of the line passes over water bodies in Bhakti Park and Wadala, both areas classified as CRZ II, where regulations limit construction activities. A total of 48 piers are proposed to be built in the CRZ II zone. The MMRDA proposed building metro car depots for the line on a plot at Owala village in Thane district and another in Vikhroli. The agency stated that the line would require two depots due to its length. The MMRDA used a drone to carry out survey work for Metro 4. The drones were fitted with 360 degrees camera that provide up to accuracy. The aerial survey takes less time than a regular survey, achieves greater accuracy and helps protect against false claims for compensation. The MMRDA appointed Systra MVA Consulting India Pvt. Ltd. as the detail design consultants for Line 4 on 9 November 2017. A consortium of DB Engineering, Louis Berger and Hill International was awarded a project management and construction management services contract for the Metro 4 project in April 2018. In October 2018, the MMRDA announced that it would construct Metro 4 along with three flyovers to minimize traffic disruption, with the metro running on the upper deck of the flyover. The three flyovers will be built at Bhayander Pada, Kasarvadavli and Anandnagar near Ghodbunder. In May 2019, MMRDA Metropolitan Commissioner R.A. Rajeev announced a modified plan to use Siddharth Colony as the interchange station with Line 2. The original plan had proposed to use the Eastern Express Highway station on Line 2B and Siddharth Colony on Line 4 as the interchange stations. However, the two stations are approximately away from Siddharth Colony and the change was made to simplify passenger transfers.
Line 4A In February 2017, the MMRDA said it was studying the feasibility of extending the corridor from Kasarvadavali to Gaimukh. In March 2017, the agency said that it was conducting a pre-feasibility study on extending the line from Wadala to Mumbai General Post Office in South Mumbai, via the Mumbai Port Trust. The proposed extension is estimated to cost 300 crore per kilometer. The extension from Kasarvadavli to Gaimukh was approved by Fadnavis at the 144th meeting of the MMRDA on 12 January 2018. The extension is estimated to cost .
Line 10 In June 2015, the MMRDA announced Metro Master Plan covering over 300 km of metro lines to decongest roads and reduce pressure on the suburban railway system. As part of the master plan it announced a brand new line named Line 10, which would serve as an extension of the announced Line 4. The line would start in and terminate in where it would intersect with the Red Line. The line is proposed to add 4 brand new stations, all of which are proposed to be elevated despite the line having some underground sections.MMRDA later stated that the Line 4, 4A, and Line 10 would form the Green Line. In December 2022 MMRDA appointed SYSTRA MVA Consulting – DB Engineering & Consulting JV as the General Consultant responsible for the execution of the line. The line is currently awaiting environmental clearance for construction as it passes through the Sanjay Gandhi National Park.
Line 11 Initially, Line 11 was announced as an extension from the Line 4 to the
Chhatrapati Shivaji Maharaj Terminus, with a proposal for 2 elevated stations and 8 underground sections running from
Wadala to the
CSMT. The Maharashtra government assigned the task of executing the project to
MMRDA. However, very early on, the project was transferred from the MMRDA to the MMRCL. This change in implementing agency saw the line being completely reworked. MMRCL announced a new alignment for the line, taking a more central route south of Byculla. The rework saw the line being converted to that of a spur line rather than a natural extension of the Green Line. It also saw the addition of new stations and the extension of the line beyond
CSMT. The line construction estimates were also doubled from Rs.8,739 crore to Rs.16,000 crore. In May 2025, as part of the
Dharavi redevelopment project, it was proposed that the northern spur of Line 11 be extended from
Anik Nagar Bus Depot to Dharavi via
Sion. This proposal was part of the
Dharavi redevelopment project, which included efforts to turn
Dharavi into a transportation hub in Mumbai.
Depot The MMRDA considered plots in Wadala, Aarey Colony and Gaimukh Nagar in Thane to build a depot for the line. On 16 October 2023, the state urban development allotted a plot of land at Mogharpada in Thane to the MMRDA at no cost. Nine hectares of the plot is reserved for use by the BMC for the
Coastal Road and a further is protected
mangrove land. The MMRDA will utilize a portion of the remaining plot to build a depot that serves Lines 4, 4A & 10. The land left over after building the depot is zoned for residential and commercial use. ==Construction==