Line 7 (Mumbai Metro)

In February 2017, the MMRDA announced that the DMRC was preparing a detailed project report (DPR) on Red line extension, a proposed 9 km (5.6 mi) extension of Red Line from Dahisar to Bhayander, via Mira Road.[7] Preliminary plans prepared jointly by MMRDA and DMRC, proposed a 9 km (5.6 mi) elevated extension of Red Line from Dahisar to Bhayander, via Mira Road. The extension will have 9 stations, with an inter-station distance of 1 km (0.62 mi). The line will run parallel to the Surat-Dahisar Highway, then turn left at Kashi Mira Junction, before passing through Mira Road-Bhayander, and terminating at Golden Nest Circle, Bhayander. The project is estimated to cost ₹3,600 crore (US$450 million).[8][9][10] The extension was approved by the Maharashtra government in September 2018, and will be implemented as Red line extension.

In March 2017, the MMRDA stated that the DMRC was conducting a feasibility study to extend the line to the T2 terminal of the airport. The proposed 3.17 km (1.97 mi) extension from Andheri to the domestic airport will pass beneath Blue Line's WEH station and is expected to cost between Rs 1,500 and 2,000 crore.[11] The extensions to Mira Road and the airport were officially announced by Chief Minister Fadnavis on 30 March 2017.[12][13][14] The alignment for the extension from Andheri to Chhatrapati Shivaji Maharaj International Terminus was approved by the State Cabinet on 12 April 2017.[15] The 3.17 km (1.97 mi) includes a 0.98 km (0.61 mi) elevated stretch and 2.11 km (1.31 mi) tunnel. The Maharashtra Cabinet approved the implementation of the extension, called Red line Airport extension, in September 2018.[16][17] Work on Airport extension was expected to begin by April 2019.[18] However, work began in early 2020 with an aim to complete by December 2021.[19]

In April 2017, the Civil Aviation Ministry provided 40 acres of land in Dahisar for the construction of the metro depot.[20][21]

The bhoomipujan ceremony for Line 7 was performed by Prime Minister Narendra Modi during his visit to Mumbai in October 2015.[22][23] Line 7 is being implemented through the engineering, procurement and construction (EPC) model.[24] The project is estimated to cost ₹6,208 crore (US$780 million). Bids for the design and construction of the corridor were split into 3 packages, and awarded by the MMRDA in April 2016.[23]

Construction work on the corridor began on 8 August 2016. The project is expected to be completed by mid-2020. The contractors are likely to complete construction of the corridor and all 14 stations within 30 months from the day of commencement of work.[25] On 18 February 2017, MMRDA officials stated that 15% of piling, pile caps and pier work on the corridor had been completed.[26] By the end of April, 25% of piling work, 60% of barricading work and 77% of the soil testing for pier foundation had been completed.[27]

On 14 March 2017, the Mumbai High Court temporarily stayed all construction activities at Metro 7's casting yard in Bandra Reclamation. The Court was hearing a PIL filed by Mohammed Furqan Ali Mohammed Qureshi who alleged that the site of the casting yard had been reserved by the Brihanmumbai Municipal Corporation (BMC) for use as a Sunni Muslim cemetery.[28][29] Piling work in Kandivli resulted in a gas pipeline bursting on 29 March 2017. The damage to the Mahanagar Gas pipeline resulted in temporary disruptions in the supply of CNG to Kandivli, Borivli, Dahisar, Mira Road and Bhayander.[30][31] Mahanagar Gas began repairing the pipeline on the evening of 31 March, and completed the work by the following evening.[32]

The MMRDA announced that construction of viaducts would begin in April 2017. The agency had completed construction of piers on several sections of the corridor, and the viaducts will be built at locations where pier caps have been built. The first viaduct was constructed in the section between JVLR to Mahanand. Construction of all pier caps along the corridor will be completed by the end of 2017.[33][34] The first U-girder, the concrete structure on which metro tracks are laid, was launched near Pathanwadi Junction in Malad on 2 May 2017.[35] In total, Metro 7 required 1,400 U-girders.[36] Work on erecting the U-girders, as well as disposal and dumping of muck generated from underground work is done only between 11:30 pm and 6:00 am. During this period, multi-axle trailers transport a U-girder weighing 170 tonne from the casting yard in Bandra to location where it is to be erected. The trailer must move slowly to avoid causing imbalance to the heavy load which can result in toppling, and takes roughly two hours to complete the journey. Lifting the girder and attaching it to the pier caps is also a difficult process and is carried out at night time. Traffic diversions are placed around the launching site to reduce the possibility of accidents. Officials erect an average of two girders every day.[37]

Line 7 is estimated to cost ₹6,208 crore (US$780 million).[23] The Asian Development Bank (ADB) will provide 43-48% of the total project cost through a loan at an interest rate of 1.4%. The Government of Maharashtra is the guarantor for the loan.[36] On 2 March 2019, the Union Ministry of Finance stated that it signed a $926 million loan agreement with the ADB to fund the construction of Metro 2 and 7. This was the single largest infrastructure loan ever extended by the ADB. The funds will be used to procure 63 six-car trainsets and for signaling and safety systems on both corridors.[42]

The proposed extension of Line 7 from Dahisar to Bhayander is estimated to cost ₹3,600 crore (US$450 million), and the underground extension to the International Airport shall cost an additional ₹600 crore (US$75 million).[43]

In April 2019, the MMRDA issued tenders for the rooftop solar PV power projects at stations on Line 7.[45]

Over the course of two weeks in March–April 2017, Mumbai residents saved nearly 4,000 trees planted on dividers and along the WEH that had been planned to be felled for metro construction. Residents replanted these trees at their own housing societies, as well as schools and other locations. Nearly 210 people and over 40 housing societies participated in the initiative coordinating their efforts through Whatsapp messages.[46]