The redevelopment of Mumbai airport’s ageing Terminal 1 was always going to disrupt airlines, but now the transition has become contentious because of the timing.

Mumbai International Airport Ltd (MIAL), operated by Adani Airport Holdings Ltd, plans to begin demolishing part of T1 in January. To make room for domestic passengers displaced by the redevelopment, MIAL wants airlines to cut or shift 265 of Mumbai’s 770 weekly international departures.

Navi Mumbai International Airport, also operated by Adani Airports, is the obvious destination for some of that traffic.

That has put airlines and the airport operator at odds. Carriers have questioned the basis for moving roughly one-third of international departures, sought records of consultations and raised concerns about the operational and financial consequences of splitting services between two airports.

Aviation experts said that the older section of T1 needs refurbishment. But they remained underconfident about whether the transition to NMIA needed to happen now and whether the ecosystem around the new airport is ready to absorb the additional traffic.

Vijai Agrawal, a former Airports Authority of India (AAI) official, said the redevelopment itself was not the problem.

“The building part is outdated, I do agree. There is no issue,” Agrawal told The Core. “But this is to be timed.”

He said Mumbai airport could have continued operating at reduced capacity for some more time, using Terminal 2 where possible, while Navi Mumbai’s connectivity and supporting infrastructure matured.

“I think the Mumbai airport is very convenient for people. So, you continue with the operation till Navi Mumbai road network, metro and all is connected properly,” he said.

“Then you can probably demolish and create more parking spaces.”

NMIA has faced persistent operational and infrastructure concerns, including cargo delays, manpower shortages, limited ground-handling equipment and screening bottlenecks. Airlines have flagged ground handling, cargo facilities and connectivity in the past, while patchy 4G/5G coverage in February and high user development fees in mid-2025 raised further concerns over passenger experience, affordability and the airport’s readiness to handle additional traffic.

Safety Versus Timing

MIAL says the redevelopment cannot simply be postponed because of the disruption it creates.

The shift involves around 265 weekly international departures across 46 airlines, with IndiGo accounting for the largest reduction at 74 flights a week, followed by Air India at 33, Akasa Air at 11, Etihad and Emirates at 10 each, Air India Express at seven and SpiceJet at five. However, the 265 flights should not be treated as 265 flights physically moving to NMIA. Some capacity could be surrendered, cancelled, shifted to other airports or otherwise reshuffled as airlines adjust their schedules.

A person familiar with the airport operator’s position from Mumbai International Airport Limited (MIAL) said the section being demolished is the older T1B structure, which is around 60 years old and nearing the end of its structural life. The redevelopment is being undertaken in phases so that operations can continue from the newer T1C section.

The person said the northern section of T1B being taken out of service represents only around one-third of T1’s 15 million passenger capacity, or about five million passengers.

The airport operator is looking to accommodate as much of that traffic as possible at Terminal 2, while airlines have also been given Navi Mumbai as an option.

The decision to proceed now, the person said, was driven by the need to address an ageing terminal without compromising safety.

“God forbid, you've seen what happened at the Delhi airport. You don't want something like that happening at the Mumbai airport. Who takes responsibility then?” the person said.

The redevelopment, according to the person, is therefore being carried out gradually rather than shutting the entire terminal at once.

“It's an ageing thing, everyone knows; it is almost reaching its life, so might as well, slow and steady in phases, demolish the terminal,” the person said.

The airport operator also argues that the shift is not as large as it may appear. According to its assessment, the immediate movement affects around 9% of Mumbai airport’s overall traffic, with the remaining 91% continuing to operate from Mumbai.

But the question is whether Navi Mumbai is ready for even that additional pressure.

A Plan That Has Changed Shape

The plan to rebuild Mumbai airport’s Terminal 1 is not new. But a review of regulatory filings and statements by the airport operator shows that the scope and execution of the project have changed significantly — from rebuilding T1B, to a proposal to demolish the entire T1 complex, and now to a phased redevelopment beginning with only a section of T1B.

The earliest evidence dates to August 2017, when a structural audit of T1B was conducted. By the 2019-20 regulatory planning period, MIAL had proposed about Rs 1,205 crore for reconstructing T1B, with AERA records explicitly stating that the existing terminal would be demolished and rebuilt. The project was part of AERA’s formal tariff process and was discussed with stakeholders in October 2020.

Reports also showed that T1B reconstruction was a concrete project, with completion targeted for March 2023. MIAL planned to keep T1A and T1C operational while T1B was rebuilt.

The project was subsequently deferred amid Covid-19 and the resulting fall in traffic. But when MIAL returned with its proposal for the Fourth Control Period, the scope had changed materially.

AERA's 2024-25 consultation documents recorded MIAL's proposal to demolish the entire T1 complex — T1A, T1B and T1C — and construct a new terminal. The justification had also broadened beyond T1B's structural condition to include security and operational issues at T1C.

The 2025 regulatory proceedings then raised questions over how such a demolition could be phased. AAI said the project could be redesigned for phased reconstruction, while IATA questioned the operational impact and the possibility that T1 closure could effectively push airlines to Navi Mumbai.

The latest development, however, is narrower.

On October 3, 2026, Adani Airports announced that redevelopment would begin in January 2027, but that only the North Section of T1B would be demolished in the first phase. The section accounts for about one-third of T1's capacity, with around five million passengers a year expected to be affected.

This creates an important question. AERA's 2024-25 record describes a plan to demolish the entire T1, while MIAL's latest announcement describes a first phase involving only part of T1B.

MIAL has not publicly indicated that the larger redevelopment has been abandoned, so the latest plan could simply represent the first stage of the same project.

Could It Have Waited?

Agrawal believes it could have.

He said the existing terminal had previously been renovated and could continue operating at reduced capacity while the new airport’s supporting infrastructure caught up.

“At least some operation you can shift to Terminal 2. But it can continue,” he said.

His argument is less against the redevelopment itself and more about the sequencing of the two projects.

“Once that is done and people are comfortable to go there, then you can probably demolish,” he said.

The concern is particularly relevant because the move is not simply about transferring aircraft operations from one terminal to another. It changes how passengers, airlines, cargo operators and airport workers access and use the Mumbai airport system.

Agrawal also pointed to the difference in airport charges between the two locations. While NMIA is offering incentives such as a waiver of landing charges in its initial period, he said such incentives primarily benefit airlines and do not necessarily translate into lower costs or greater convenience for passengers.

“Landing charges are free for a year, but it does not translate into benefits for passengers. It is incentivising the airlines, not the passenger,” he said.

A New Airport Still Finding Its Feet

Vandana Singh, an aviation expert, had a more measured view.

She agrees that Terminal 1 needs refurbishment and that moving traffic to Navi Mumbai was always part of the broader plan to decongest Mumbai airport.

But she said the timing becomes questionable if the new airport's systems are not yet operating smoothly.

“If proper training has not been done, if the slowdown, if the process is not in line as expected, then they should have probably extended it by a bit and said, given it a firm approval as to NMIA can actually take all this pressure,” Singh said.

She said an extension of a few months could have allowed NMIA to stabilise before taking on additional traffic.

“At the most, they could have taken it to March, but they have to do this forced shift,” she said.

At the same time, Singh cautioned that there is no perfect moment for a transition of this scale.

“No timing would be right,” she said, arguing that eventually airlines and other stakeholders have to make the transition and allow the new airport to scale up.

That is what makes the current shift particularly difficult: the industry is effectively being asked to adapt to two moving pieces at the same time.

MIAL first communicated the T1 redevelopment and transition plan to airlines through an Airport Users Consultative Committee meeting in March 2024. However, the current plan to shift operations to Navi Mumbai took shape in August-September 2026, ahead of T1’s January 2027 demolition, prompting IATA to allege inadequate airline consultation.

More Than An Airport Building

For Singh, the larger issue is not whether NMIA has a runway, terminal or passenger capacity. It is whether the ecosystem around it is ready.

“When it comes to ground handling, when it comes to maintenance, when it comes to catering, cargo, hotels, connectivity—you see, this is the main thing,” she said.

“We are building fantastic airports. But what about the connectivity and the ecosystem around it? That is a question mark.”

The concern comes as cargo operators and other businesses already using NMIA have reported delays and operational difficulties.

In terms of the airport connectivity, there is no direct Mumbai Metro connection to the airport yet. Navi Mumbai Metro Line 1 is operational in Navi Mumbai, but it does not provide a direct airport link. The proposed Metro Line 8 between CSMIA and NMIA is still a future project, so it cannot be counted as a January 2027 solution. The 35-km Line 8 was cleared in principle in January 2026, but construction and commissioning are still ahead.

That makes the transition from T1 more complicated because airlines do not operate in isolation. A move also requires ground handlers, cargo facilities, maintenance providers, caterers, employees and passengers to adjust to a different airport.

Singh described the shift as a “forced movement”, arguing that the airport may be structurally ready while the ecosystem around it is still catching up.

Meanwhile, Adani Airports is stepping up supporting infrastructure at Navi Mumbai International Airport as it prepares for the Winter Schedule. NMIA has expanded its ground transport network across Mumbai, Navi Mumbai, Pune and the wider MMR, including additional MSRTC, NMMT and private bus services, app-based taxis and a complimentary shuttle to Mumbai’s Chhatrapati Shivaji Maharaj International Airport.

The airport has also expanded its airline-support infrastructure, with its TajSATS flight kitchen currently serving more than 40 departing flights a day and capable of producing 7,500 meals daily, scalable to 15,000 as flight movements and passenger traffic increase.