Mumbai’s T1 Rebuild Squeezes Sold International Winter Slots

Mumbai International Airport has told 46 airlines to free 265 of Terminal 2’s 770 weekly international departure slots so Terminal 1 can be rebuilt. The Civil Aviation Ministry paused that plan on October 6 and called both sides back for a meeting on October 13.

The operator, Mumbai International Airport Ltd (MIAL), still wants room at T2 for about five million domestic passengers a year who must leave the 1965 Terminal 1. Airlines say those seats sit in a winter schedule approved in June, with aircraft, crews, and tickets already committed. The only other runway on offer is Navi Mumbai International Airport, 45 kilometers away, which opened on December 25, 2025, and is also controlled by the Adani Group.

The Ministry Paused the Cut, Then MIAL Asked Again

MIAL, a joint venture of Adani Airport Holdings and the Airports Authority of India, wrote to carriers on October 1 with a 33% cut in T2 international departures from 11:59 p.m. on October 25. Airlines that missed a September 16 session, and that had not filed transition plans by September 25, were told the operator would pick the flights itself if they did not name them by 4 p.m. on October 6.

The Civil Aviation Secretary then put the discontinuation on hold and told the operator to come back with a plan the airlines could accept. The ministry also said approvals from the Directorate General of Civil Aviation, the Bureau of Civil Aviation Security, and the state government had to be in place before any shift. MIAL’s major development plan for Terminal 1 is still waiting on that clearance.

The pause did not kill the ask. In a fresh note ahead of October 13, MIAL said senior Adani Airports executives would walk through a partial demolition of T1 and the need to move about five million passengers a year onto T2. The operator’s math is blunt: extra domestic traffic of that size at T2 requires a matching temporary cut in international traffic of about five million. It asked airlines that had already talked about traffic cuts to arrive with one joint, usable proposal.

On structural safety, MIAL said audit reports had been reviewed by the relevant regulators and that extracts were already public. A spokesperson said T1 demolition had been due in mid-2025 and was held back because Navi Mumbai was not ready, and that work is now due to start in January 2027, with a new T1 due in 2029 to 2030. Carriers, the spokesperson said, may move to Navi Mumbai or suspend the affected flights until then, and historic slot rights would be honoured when the new terminal opens.

Arun Bansal, chief executive of Adani Airport, put the operator’s logic in one line: an airline can decide on its own business case, and the airport’s case is that T1 has to shut.

THE PATH TO THE OCTOBER 13 MEETING

1. December 25, 2025: Navi Mumbai International Airport opens to commercial flights, with Adani holding a 74% stake.
2. June 2026: The Winter 2026 to 2027 slot list for Mumbai is approved, and airlines lock aircraft, crews, and ticket sales against it.
3. September 9, 2026: The International Air Transport Association writes to the ministry opposing a forced shift of about one third of each airline’s international work.
4. October 1, 2026: MIAL tells 46 airlines to discontinue 265 of 770 weekly international departure slots from October 25.
5. October 6, 2026: The ministry puts that plan on hold and sends both sides back to talks.
6. October 13, 2026: MIAL and the Airline Operators Committee meet on a transition plan the ministry still has to accept.

A further session around October 20 has been discussed for a final paper. Until that paper exists, the October 25 start date is not live. The rebuild calendar has not gone away with it.

IndiGo Would Lose 74 Departures a Week

The October 1 schedule named the flights, not a vague share of the pie. IndiGo, which runs 224 weekly international departures from Mumbai, was listed for 74 cuts, which would leave 150. Air India, on 100 weekly overseas departures, was listed for 33, which would leave 67. Those two Indian carriers take the heaviest hit because they hold the most T2 international times.

MIAL’S PROPOSED WEEKLY INTERNATIONAL CUTS AT T2

Air India Express was listed for seven weekly slots and SpiceJet for five. From 00:01 on October 26, MIAL said it would hand vacated T2 counters, baggage belts, gates, and office space to domestic operators moving off T1. That is the swap the 265 slots are meant to buy: international processing gear turned over to domestic flights so the old terminal can come down.

Airlines have asked a simpler question than the ownership plot. They want to know how a loss of about five million domestic passengers’ worth of T1 space turns into the removal of about a third of Mumbai’s international departures, and what became of a T2 expansion that was itself supposed to add about five million passengers a year.

The Winter Schedule Was Already Sold in June

Winter flying from Mumbai is not a whiteboard exercise in October. The slot list for Winter 2026 to 2027 was approved in June. By the time MIAL sent the 265-flight notice, aircraft rotations, crew bases, and seats on sale were already built around those times. A ticket sold in July for a late-October departure out of T2 is a legal and operational fact, not a draft.

That is why the fight is not only about which airport looks nicer. Pulling a departure after the season is on sale means re-accommodating passengers, moving crews, and, if the flight dies instead of moving, parking an aircraft that was rostered for Mumbai. IATA told the ministry that international airlines fix schedules, aircraft, sales inventory, and staff many months ahead, and that both the ministry’s slot rules and international practice require a transparent capacity check before those times are taken away.

The association has already told MIAL, in an earlier Mumbai slot dispute, that temporary capacity cuts need prior consultation rather than a surprise list, and that historic rights for later seasons must be kept. Albert Tjoeng, IATA’s head of corporate communications, later thanked the ministry for stepping in on this round and said any big cut should rest on a clear reading of demand and capacity, with enough time to limit the mess for airlines and passengers.

People holding through-tickets are already mixing up which Mumbai airport their domestic leg uses. A short connection that works inside T2 does not survive a hop across the harbour. That confusion will land on the carrier that sold the ticket, not on the slide deck that described a temporary transition.

What the October 13 Meeting Has to Settle

The Airline Operators Committee, which speaks for every carrier at the airport, wrote to MIAL’s chief airport officer on October 9 with six items it wants on the table. The committee said member airlines support a safe, timely rebuild of T1. It also said the 33% cut was not discussed with the committee or the affected airlines and is being pushed as a unilateral step.

WHAT THE AIRLINE COMMITTEE PUT ON THE AGENDA

• Safety papers: Independent consultant reports MIAL has cited for structural risk at T1, which the committee wants to read rather than hear summarised.
• Rebuild plan: Scope, phase-by-phase work, technical assessments, firm dates, and the capacity hit during each phase.
• T2 expansion: Status, scope, and timing of the extra five million passengers a year that T2 was supposed to absorb.
• 2026 capacity use: Month-by-month actual load against declared capacity at both terminals, plus the demand-capacity study behind any cut.
• The 33% math: How the reduction was built, how it was sent to airlines, and what it does to approved Winter 2026 to 2027 slots.
• Other options: Alternatives MIAL considered, including a temporary passenger-processing facility, and a check against the ministry’s slot rules.

IATA has told carriers to walk into that room with the ministry’s 2013 slot allocation guidelines and the globally used rules for airport slots, which call for an open capacity declaration, consultation, and time to rework a season. It also wants historic Mumbai slots protected while any squeeze lasts, and it does not want a cut at T2 used as a directive to move a set share of flying to Navi Mumbai.

MIAL’s brief for the same meeting is the reverse. It wants a joint airline paper that actually reduces T2 traffic so T1 can come down. Safety reports, in the operator’s account, have already been seen by regulators. The gap the October 13 session has to close is whether five million domestic passengers can be processed at T2 without deleting 265 international departures, or whether that number is a negotiating opener.

A Landing-Fee Waiver Does Not Move the Crews

Navi Mumbai is not a paper airport. It opened on December 25, 2025, with a first-phase capacity of 20 million passengers a year and a long-term design for 90 million. International flying from there has already started. What airlines are being asked to do is treat it, on a few weeks’ notice, as a substitute for T2 on routes that were sold as Mumbai.

NAVI MUMBAI AS THE OFFERED EXIT

• The distance: About 45 kilometers from Mumbai airport, with a direct metro link not expected until 2031.
• The passenger fee: AERA set the international departing user development fee at ₹1,225, below the ₹1,467 Navi Mumbai International Airport Ltd sought, and the domestic fee at ₹620, below ₹742.
• The landing bait: AERA approved a 100% landing-charge waiver in year one for new international passenger routes from Navi Mumbai, then 50% in year two, with a further 25% in year three on long-haul sectors over 5,000 kilometers.
• The operator line: Historic Mumbai slots would be honoured once the new T1 opens in 2029 to 2030, and the move is described as temporary.

Airline filings that set Navi Mumbai UDF against Mumbai rates put international embarking charges at ₹1,225 versus ₹615 at the existing airport, and domestic embarking at ₹620 versus ₹175. Vouchers have been floated to offset the UDF gap. A cheaper landing fee in year one does not erase a passenger charge that is about double Mumbai’s international rate in that filing, and it does not put a metro under the terminal.

Catering, Widebodies, and the Metro Wait

IATA’s September 9 letter went past ownership and into the kit list a long-haul operation needs. It asked whether the maintenance shop at Navi Mumbai holds the type approvals for the aircraft international airlines actually fly, whether there are stands and ground tools for widebodies, and whether cargo, crew transport, and crew beds are in place. It said airlines understood the kitchen was dry catering, which is a poor fit for long-haul trays. It also said a full operational-readiness transfer, the rehearsal airports run with airlines before a move, had not been shown for this shift.

MIAL has pointed to Navi Mumbai as a ready alternative inside the same metro region. IATA’s reply is that a dual-airport system works when the receiving airport is actually ready, the move is voluntary, and the two slot pools are run as separate coordinated resources. A 100% landing waiver can start a new route. It cannot invent a second ground team, a second crew hotel, or a two-hour road transfer for a passenger who bought a T2 connection.

Freight has already been used as the test. Some cargo operators paused or rerouted Mumbai freighter work after a mandatory shift to Navi Mumbai, which is a warning the passenger argument keeps circling: the new airport can take an airplane, and still fail as a gateway if the rest of the chain is not there.

For Long-Haul Fleets, Navi Mumbai Means a Second Ground Operation

Stefan Gumuseli, Air France-KLM’s general manager for India and the Middle East, said in late September that the group would not split its Mumbai passenger flying. It plans 20 weekly Mumbai flights in the winter season that starts in November, up from 14, as part of 54 weekly India flights, up from 42. Cargo can go to Navi Mumbai. The passenger product, he said, stays at one airport.

We are an airline that operates on efficiency. In one city, we cannot operate to two different airports, especially on long-haul.

Stefan Gumuseli, general manager for India and the Middle East, Air France-KLM

He said a two-airport setup can work when the fields serve different catchments, and cited Tokyo. Mumbai and Navi Mumbai, in that reading, share one catchment, so a split means new ground staff, new handling contracts, and a training bill for an operation that already exists at T2. If T2 capacity fell to a level the group could not use, he said, the whole passenger operation would move. Splitting it would not.

IATA put the same objection in writing on September 9, with 370-plus airline members in 120 countries behind the letter.

IATA is fundamentally opposed to forced airline relocations. Any transfer of operations should be voluntary, commercially and operationally viable, and supported by a comprehensive operational readiness and airport transfer process (ORAT), consulted upon and agreed to by airline stakeholders.

International Air Transport Association, letter to the Civil Aviation Ministry, September 9, 2026

Mark D. Martin, founder of Martin Consulting in Delhi, said the hard problem at Navi Mumbai has been connectivity back to the old terminal, and that the local catchment for a long-haul carrier is thin next to Mumbai’s established hub. That is the second-order bind the October 13 meeting cannot slide past with a fee waiver. T1 still has to be rebuilt. Five million domestic passengers still need a roof. The winter list was sold as Mumbai T2, and Navi Mumbai is still 45 kilometers and a missing metro away from that promise.

The ministry can keep the October 25 cut on hold. It still has to approve a Terminal 1 plan, and a way to process those five million people, before January 2027. Airlines can keep saying they support the rebuild. They still have to name, flight by flight, what they will do with a sold winter if T2 space is taken anyway.