Keystone Realtors Limited, which operates under the Rustomjee brand, has been appointed the Construction and Development Agency for the Guru Tegh Bahadur Nagar (GTB Nagar) colony in Sion Koliwada. Keystone Realtors got approval for its proposal to redevelop 25 buildings in GTB Nagar of Mumbai's Sion Koliwada that have a gross development value of Rs 4,521 crore, working in collaboration with the Maharashtra Housing and Area Development Authority, which gave a letter of approval to the company. This is not an incremental land parcel added to a developer's roster; it is MHADA's first redevelopment project on private land to be implemented through the Construction and Development Agency model, and the agreements were formalised with Boman Irani, Managing Director of Keystone Realtors (Rustomjee Group), present at MHADA Headquarters in Bandra alongside senior MHADA officials.
The scale of the commitment is unusual even by Mumbai's redevelopment standards. The redevelopment, spread across a plot area of 11.19 acres (45,308 square metres), will rehabilitate around 1,200 society members and unlock a saleable area of approximately 20.7 lakh square feet for Keystone. The project will unlock approximately 20.7 lakh square feet of saleable area, with each eligible family receiving a complimentary home measuring 635 square feet, while MHADA will gain 25,700 square metres of built-up space as housing stock. In March 2026, the process moved from approval to execution: all the cooperative housing societies in the project executed the Tripartite Development Agreement with MHADA and the appointed Construction and Development Agency, Rustomjee Group, and the Construction-cum-Development Agreement was also formally signed.
The GTB Nagar colony has a specific, documented history that explains why this redevelopment matters to Mumbai's housing stock. Constructed in 1958 for post-Independence migrants, the buildings in GTB Nagar were declared unsafe by the Brihanmumbai Municipal Corporation in 2020 and subsequently demolished, with residents having to seek alternative accommodation on their own. In response to appeals by tenant societies, the state government approved the redevelopment of the site through MHADA, despite the land being privately owned. The policy framework was finalised by Chief Minister Devendra Fadnavis, with Cabinet approval granted on February 14, 2024 for redevelopment under Regulation 33(9) through a Construction and Development Agency, followed by a Government Resolution dated February 23, 2024 granting MHADA Special Planning Authority status for the project.
The redevelopment falls under a specific regulatory route that shapes what gets built. Under this redevelopment, three modern residential towers ranging from 39 to 48 storeys will be constructed for approximately 1,200 eligible beneficiaries, with a minimum FSI of 4.5 (inclusive of fungible FSI) made available under Development Control Regulation 33(9). The rehabilitation component is substantial in human terms: the redevelopment initiative encompasses 25 buildings across 11.19 acres and is expected to benefit over 1,400 families, including 1,200 Sindhi refugee families and 200 slum dwellers. For Rustomjee, the free-sale component built on top of this rehabilitation obligation is what supports the branded residences now taking shape on the site — configured across 1, 2 and 3 BHK formats within the same footprint as the rehab towers.
Keystone Realtors Limited was incorporated in Mumbai under the Companies Act, 1956 on November 6, 1995, and converted into a public company in 2022, trading on the NSE and BSE since its November 2022 listing. Over three decades, the company built the scale that made it MHADA's choice for a redevelopment of this size: the company has approximately 37 completed projects, 16 ongoing projects, and 28 forthcoming projects across the Mumbai Metropolitan Region. Its portfolio spans price points and geographies, from Rustomjee Elements, a large gated community in Upper Juhu, and Rustomjee Crown, a 5.75-acre high-rise development at Prabhadevi in South Mumbai, to townships in Thane and mid-income developments in the eastern and western suburbs. Financially, the company entered the GTB Nagar mandate on strong momentum: Keystone Realtors posted record FY26 pre-sales of Rs 40.2 billion with collections of Rs 26.2 billion, and Q4 pre-sales rose 53% year-on-year to Rs 1,346 crore with collections growing 14% to Rs 853 crore.
Redevelopment, specifically, is core to how Keystone Realtors structures its growth. As part of its business model, the company enters into joint property agreements, redevelopment agreements with landowners, builders or societies, and slum rehabilitation property, which requires lower upfront capital investment compared to direct acquisition of land parcels. GTB Nagar is the largest expression of that strategy to date, and the market responded accordingly: shares surged 7-10% following the GTB Nagar LoA announcement on July 1, 2025, with the stock trading between Rs 638-697 in early July 2025, approaching its 52-week high of Rs 801.
GTB Nagar sits within Sion Koliwada, a locality whose character has been shaped by successive waves of settlement. Guru Tegh Bahadur Nagar, formerly Koliwada, is a residential area in Sion named after the ninth Guru of Sikhism, originally home to Mumbai's indigenous Koli community before a colony was built after Partition for the rehabilitation of Sikh and Hindu refugees from what is now Pakistan. That layered history is precisely why the site qualifies for cluster redevelopment: many of the tenements and structures first built for the refugees are now in a poor state and are awaiting demolition and rebuilding across the wider precinct, of which the Rustomjee project is the flagship instance.
For a buyer evaluating this address, connectivity is the strongest argument. Sion Koliwada is located in the centre of Mumbai, connected to major parts of the city via Sion railway station, and is about 16 to 17 km from CSMT and roughly 5 km from Bandra. Guru Tegh Bahadur Nagar Railway Station on the Harbour Line links Wadala Road to Panvel and sits next to the locale, while GTB Nagar Station on the Monorail Line 1, about a kilometre away, connects it to Chembur and Sant Gadge Maharaj Chowk. Road access is equally direct: Eastern Express Highway is less than a kilometre away and connects the locale to Chhatrapati Shivaji Maharaj Terminus and Thane, while commercial hubs such as Bandra Kurla Complex, Peninsula Business Park and Kohinoor Business Park are 7-9 km away. Sion Koliwada is about 13 km from Chhatrapati Shivaji Maharaj International Airport via the Western Express Highway.
Social infrastructure around the site is already established rather than aspirational. A robust local infrastructure ensures access to schools, colleges including Guru Nanak Khalsa College, hospitals, markets, shops, and eateries, all within walking distance. The locality's residents rate it favourably on practical metrics too: residents of Sion Koliwada rated this locality at 4.4 out of 5 for connectivity and 4 out of 5 for safety.
Prices in the immediate GTB Nagar micro-market give an indication of the demand base the redevelopment is tapping into. The average property price in GTB Nagar currently ranges from roughly Rs 15,714 to Rs 18,000 per square foot, with rentals for 1-3 BHK flats ranging from Rs 35,000 to Rs 60,000 per month. Sion at large, of which GTB Nagar and Sion Koliwada form a part, is priced somewhat higher on aggregate: Sion has 1,550 listings on marketplaces with a median price of Rs 28.1 K per square foot, against a Sion average price of Rs 28.1 K per square foot compared to a citywide Mumbai average of Rs 38.6 K per square foot — underlining that this pocket of central Mumbai still trades at a relative discount to the city while offering harbour-line and monorail access that many western-suburb addresses lack.
A buyer looking at Rustomjee's GTB Nagar address is essentially buying into two things simultaneously: a large-format branded redevelopment executed by a listed, three-decade-old Mumbai developer, and a central-suburban location with harbour-line, monorail and expressway access that is still priced below the city average. The rehabilitation-linked structure of the project — a minimum Floor Space Index of 4.0 excluding fungible FSI, offering larger, modern homes to existing tenants at no cost while making increased saleable area available to the developer — is also why the free-sale apartments on this site sit within the same integrated masterplan as the rehab towers, rather than as a standalone gated project bolted onto an existing pocket. For Rustomjee, GTB Nagar extends a redevelopment track record already visible elsewhere in the city, from Prabhadevi to Bhandup, into what the company itself has called one of the largest such initiatives Mumbai has seen.