Adani Airport will proceed with the phased redevelopment of Mumbai airport’s Terminal 1 from January 2027, despite airlines rejecting a proposal to temporarily reduce international departure slots and shift part of their operations to Navi Mumbai airport. Mumbai and Navi Mumbai airports are operated by Adani Airport Holdings, which manages eight airports and handles 23 per cent of India’s domestic air passenger traffic. Mumbai airport handled nearly 16 mn international passengers in FY26, while its annual capacity is 55 mn passengers. The operator said the redevelopment would leave most passenger traffic unaffected. It plans to temporarily discontinue 265 of 770 weekly international departure slots at Terminal 2 from 25 October, allowing domestic services displaced from Terminal 1 to use the freed capacity. The proposed cuts affect 46 airlines, including IndiGo, Air India, Akasa Air, Air India Express, Emirates, Etihad Airways and British Airways. The first phase involves the north section of Terminal 1B and represents about a third of the airport’s capacity. Adani Airport said around 5 mn passengers, or about 9 per cent of annual traffic, would be temporarily deoperationalised. The redevelopment is expected to raise Terminal 1’s annual capacity by 33 per cent, from 15 mn to 20 mn passengers, after which historical slots and additional slots will be restored. Airlines have rejected the proposed reduction, saying their support for the terminal project did not constitute consent to withdrawing established international slots. The Airline Operators Committee-Mumbai has sought the technical and operational basis for the proposed 33 per cent reduction and has escalated the matter to the Directorate General of Civil Aviation, the Ministry of Civil Aviation and the Airports Economic Regulatory Authority. Adani Airport has asked carriers to identify slots for temporary discontinuation by 4 pm on 6 October, warning that it may select them if airlines do not respond. The operator has offered cash vouchers to international passengers moved to Navi Mumbai to offset differences in user fees, while Navi Mumbai airport is offering a 100 per cent discount on landing fees for new international flights. The International Air Transport Association has opposed forced relocations, and Air France-KLM has said splitting its operations between the two airports is not an option.