MUMBAI, Sept. 29 -- The long-awaited Metro Line 8 project, which will provide a direct mass transit link between Mumbai's Chhatrapati Shivaji Maharaj International Airport (CSMIA) and the upcoming Navi Mumbai International Airport (NMIA), has reached a crucial milestone. The detailed project report (DPR) has been submitted to the state government for approval after receiving clearances from both the urban development and finance departments, senior officials confirmed. According to the DPR, the 34.89-km corridor will cost an estimated Rs.23,000 crore and is being planned on a public-private partnership (PPP) model, similar to Mumbai Metro Line 1 (Versova-Ghatkopar). The City and Industrial Development Corporation (Cidco), the nodal agency for the project, has sought 20% viability gap funding (VGF) each from the state and Centre, with the balance investment to come from the private build-operate-transfer (BOT) partner. The line will feature 20 stations-six underground and 14 elevated-with projected daily ridership expected to reach 1,030,000 passengers by 2031. Officials said the corridor will serve as a "seamless connector" across the Mumbai Metropolitan Region (MMR), integrating with at least six other Metro lines as well as suburban rail and bus terminals. In addition, the corridor will be linked to the Lokmanya Tilak Terminus (LTT), enabling outstation travellers to directly access either airport via Metro. A senior official said, "This project will offer end-to-end connectivity between MMR's two international airports and integrate with major rail and road hubs. It will be a backbone for passenger and workforce movement once NMIA becomes operational." Cidco has begun a peer review of the DPR, covering alignment, traffic and environment studies, integration with existing networks, land acquisition, and financing. The review will be conducted by an independent third party, with suggestions to be incorporated before the proposal is finalised. "We want the DPR to be foolproof," said Vijay Singhal, managing director, Cidco. "A tender has been floated to appoint an agency for peer review as well as a transactional advisor. Only after this process will we move forward with seeking viability gap funding."...