Mumbai airport T1 redevelopment matter reaches MoCA. What is the issue and why are airlines opposed?

So, why does the redevelopment of T1 require such a large-scale change in international operations, and what are airlines objecting to?

The redevelopment of Mumbai airport’s Terminal 1 is set to affect hundreds of international flights, with airport operator Adani Airport-owned Mumbai International Airport Ltd (MIAL) proposing to shift 265 of its 770 weekly international departures to Navi Mumbai from October 25.

.Airlines have opposed the move, questioning the basis for the reduction and saying their winter schedules have already been finalised (PTI File)

Airlines have opposed the move, questioning the basis for the reduction and saying their winter schedules have already been finalised, to the extent that the issue has now reached the Civil Aviation Ministry, which has called MIAL and airlines for a meeting on Tuesday.

The meeting comes on the same day that MIAL has asked airlines to identify the international slots they are willing to temporarily discontinue; failing which, the airport operator has said it may decide which services to withdraw based on operational considerations.

So, why does the redevelopment of T1 require such a large-scale change in international operations, and what are airlines objecting to?

Why is T1 being redeveloped?

Mumbai International Airport, one of the busiest in the country, has two terminals: T1 and T2. While T1 is used for domestic operations, international flights operate from T2.

The redevelopment of T1 is not a new proposal. According to a consultation paper submitted by MIAL to the Airports Economic Regulatory Authority of India (AERA) in 2025, the T1B building is more than 65 years old, having been constructed between 1957 and 1964. MIAL said the structure had developed various defects, including structural distress and seepage/leakage, which could not be addressed through repair activities.

A structural audit conducted by an independent third-party agency recommended demolition of a significant portion of the building. MIAL also submitted a structural study conducted by IIT Mumbai, which found signs of deterioration in T1B, including corrosion of structural elements, spalling of concrete, exposed reinforcement bars and seepage and leakage.

The IIT study found that the reinforced concrete structural elements on the terraces of T1B were severely deteriorated, with longitudinal cracks caused by corrosion. At one location, the loss of reinforcement in a column was more than 50%. Its corrosion analysis showed more than 90% chances of corrosion in the structural members of T1B.

The study, however, did not find the same extent of structural and non-structural defects across all parts of T1. It found T1C to be mostly free of structural and non-structural defects, while T1A was described as an approximately 30-year-old disused building with deterioration, but no major structural distress was observed during the study.

MIAL had proposed reconstruction of T1 during the third control period, covering 2019-24, for an area of 72,414 square metres. Airports Authority of India (AAI) had allowed the reconstruction of T1B, citing structural safety concerns, at a cost of ₹832 crore at the consultation paper stage. MIAL subsequently deferred the project due to the impact of COVID-19 and the resulting reduction in air traffic.

It later proposed reconstructing T1 to increase its passenger-handling capacity from 15 million passengers per annum (MPPA) to 20 MPPA.

The reconstruction of T1 will commence in January 2027 and is estimated to be completed in three years. Demolition work for Terminal 1 was scheduled to commence in November 2025, with construction expected to be completed by September 2028.

So why does the redevelopment affect international flights?

This is where the current dispute begins. T1 currently handles around 15 MPPA of domestic traffic. In its submission to AERA, MIAL said that once operations at the existing terminal were halted for demolition and reconstruction, a portion of the traffic would be accommodated at T2, while the remaining traffic was expected to shift to the newly inaugurated Navi Mumbai International Airport.

This creates a capacity problem. Domestic traffic displaced from T1 has to be accommodated elsewhere, while T2 already handles international operations. The current proposal to temporarily discontinue 265 weekly international departures from Mumbai and to shift operations to Navi Mumbai is linked to this capacity reshuffling.

The plan to use Navi Mumbai to absorb traffic displaced by T1 redevelopment was therefore part of MIAL’s planning as per the consultation paper submitted to AERA. However, industry stakeholders have sought greater clarity on how the transition would work.

What airlines and IATA raised?

The AERA consultation paper records concerns raised by industry stakeholders about the impact of T1’s closure and the assumptions around the shift of traffic to Navi Mumbai.

The Federation of Indian Airlines (FIA) raised concerns about the downward trend in MIAL’s traffic forecast methodology. It said certain airlines projected a progressive increase in traffic and sought an explanation for the rationale behind the forecasts.

International Air Transport Association (IATA), which represents more than 360 airlines globally, sought additional information on MIAL’s capital expenditure projects, including their timelines, dependencies and expected benefits. It also said claims about increasing aircraft movements from 46 to more than 50 per hour should be substantiated through detailed research.

IATA also sought details on the impact of T1 closure and re-provisioning, including how displaced demand would be accommodated at T2 and the assumptions regarding relocation of airlines to Navi Mumbai. AERA’s independent consultant also discussed with MIAL’s design team whether T1 reconstruction could be carried out using a modular approach, initially providing 10 MPPA and later expanding to 20 MPPA based on an actual traffic assessment after the Navi Mumbai airport opened. MIAL said such modular construction was not feasible due to the spatial constraints and the shape of the available land parcel.

In a letter to the ministry on September 9, IATA also sought the Civil Aviation Ministry’s intervention in the matter. It opposed the partial relocation of international flights and termed it “forceful relocation”.

Individual airlines have also raised concerns over splitting operations between Mumbai and Navi Mumbai. Air France-KLM, for instance, has said splitting its operations between the two airports does not make sense, citing the operational difficulties of dividing its teams and arrangements between two locations.

What did the airport operator say?

On October 3, Adani Airports Holding Ltd (AAHL) said 91% of Mumbai airport’s passenger traffic will remain unaffected by the demolition of the north section of T1 for redevelopment and the subsequent relocation of partial operations to T2 and Navi Mumbai International Airport.

T1 redevelopment will begin from January 2027 and increase its capacity by 33%, AAHL said. It said extensive consultations with airlines on the future of T1 had been ongoing since 2020, and that the proposed redevelopment had also been presented to AERA and subsequently incorporated into the approved tariff framework.

“Of Mumbai airport’s approximately 55 million passengers per annum, only around 5 MPPA (about 9%) will be temporarily de-operationalised,” AAHL said. According to MIAL, the reconstruction of T1 will not have any impact on airside operations (including the runway)

AAHL said it would support airlines through the transition and assist with the migration of services. Navi Mumbai Airport is offering a 100% discount on landing fees for new international flights. In addition, it plans to offer cash vouchers to international passengers to offset the difference in the User Development Fee (UDF) levied at Navi Mumbai and Mumbai airports.

According to reports, the Airline Operators Committee (AOC), a committee representing airlines operating at the airport, wrote to MIAL on October 4 seeking details on the basis for its proposal to shift 33% of international flights to Navi Mumbai airport. The AOC also sought records of consultations held on the issue since 2020, noting that the Adani Group took over operations of Mumbai airport only in 2021. It also asked for minutes of meetings held as part of consultations since 2022, as well as monthly data on capacity utilisation at Mumbai airport’s T1 and T2 terminals.

Why is the October 6 MoCA meeting important?

The October 6 meeting called by civil aviation secretary Samir Kumar Sinha comes at a crucial point, with MIAL’s 4 pm deadline for airlines to identify international slots they are willing to temporarily discontinue falling on the same day.

The meeting is expected to focus on the basis for MIAL’s proposed reduction of 265 weekly international departures, the capacity available at Mumbai and Navi Mumbai during the T1 redevelopment, and how domestic traffic displaced by the closure of T1 will be handled at T2. Airlines are also likely to seek clarity on the impact on their existing slots and winter schedules, and what happens if they do not agree to voluntarily discontinue services.

The dispute, therefore, is not over the redevelopment of T1, but over how airport capacity will be managed during the transition and how the impact will be shared between Mumbai and Navi Mumbai airports.