The proposed Karnala-Sai-Chirner (KSC) New Town, also known as Mumbai 3.0, is planned across 124 villages in Raigad district, near Navi Mumbai.

MMRDA, appointed New Town Development Authority, is planning Karnala-Sai Chirner (KSC) New Town across 323.44 sq km and 124 villages in Uran, Pen and Panvel talukas, Raigad. About 104 sq km is developable; the rest includes villages, forests and green areas. The authority is preparing a land-use plan, expected by end-August, and a masterplan with Singapore-based Surbana Jurong.

Land acquisition began in March 2026. Landowners can opt for 22.5% developed land, monetary compensation, or transferable development rights (TDR) or floor space index (FSI) compensation. Some villages oppose acquisition, slowing parts of the land-use survey.

The 21.8-km Atal Setu opened in 2024, and Navi Mumbai International Airport is expected to support development. MMRDA says meaningful returns are unlikely for five to 10 years; success depends on transport, jobs, utilities and planned development. Knight Frank’s Gulam Zia said reliable mass transport and local employment are critical to avoid dependence on Mumbai. NeoLiv’s Mohit Malhotra and Womeki Group’s Garuav K Singh cited opportunities for residential, leisure and employment-led development.

The MMRDA Karnala Sai Chirner (KSC) Navnagar Virodhi Samiti appealed to villagers whose homes and farmland fall within the proposed Third Mumbai development not to sell ancestral land cheaply. It said the government had tried five times since 2003 to acquire their land, including a 2006 attempt linked to Reliance’s Maha-Mumbai SEZ; villagers fought legally and through protests for five years and won.

The Samiti alleged brokers were misleading farmers and making false promises to young people. It cited Atal Setu and urbanisation as drivers of rising land values, saying land near JNPT and Navi Mumbai was worth over ₹1 crore per guntha. A 2017 Raigad Collector order set compensation for NHIA-affected farmers at ₹58.80 lakh per guntha, it said. The group warned against sales for ₹2–4 lakh per guntha and urged villagers to unite against MMRDA. President and former IRS officer Sudhakar Patil said 5,000 copies of the letter would be distributed in Karnala, Sai and Chirner and circulated on WhatsApp.

• Surveys for Karnala-Sai-Chirner New Town, also called Third Mumbai, in Raigad will begin in 2025 across 124 villages and 323.44 sq km. Nearly half the area is hills, forests and farmland.
• MMRDA will appoint a consultant for drone-based aerial assessments, Lidar studies, ground verification, land-ownership data and a GIS-based map. Initial surveys are expected to take six to eight months.
• A separate private entity will prepare a vision document, comprehensive master plan and development strategy, expected by August 2026.
• The new town is envisioned as a tech hub, with 65% of the nation’s data centres projected to be located there. It is part of Maharashtra’s plan to raise Mumbai Metropolitan Region GDP to $300 billion by 2029, aligned with NITI Aayog’s vision. MMRDA and the World Economic Forum signed an MoU in September to promote regional economic growth. The regional plan was first outlined in 2013.

The Mumbai Metropolitan Region Development Authority (MMRDA) officially named the Third Mumbai Karnala-Sai-Chirner New Town (KSC New Town) on October 21. The name honours three villages among 124 in Raigad district. Also known as the Navi Mumbai Airport Influence Notified Area (NAINA), the area was announced in 2013 to prevent haphazard growth around the airport; it is planned as an environment-friendly Smart City township spanning 323.44 sq km.

Maharashtra issued three notifications on October 15 appointing MMRDA as the New Town Development Authority. MMRDA will prepare Detailed Planning Proposals and Development Control & Promotion Regulations and may acquire land. CIDCO will cease to be Special Planning Authority for 33 Khopta New Town villages; the peripheral area around Pen Municipal Council was excluded.

The 124 villages comprise 80 in NAINA, 33 in Khopta New Town Notified Area, two in the Mumbai Metropolitan Regional Plan and nine in the Raigad Regional Plan. MMRDA sought the appointment in August 2023 to capture land-value gains around the MTHL and make it economically viable. The 21.8-km sea link cost ₹17,843 crore; 7,25,746 vehicles used it in August.