An engineering planning error on the Mumbai Metro Line 7A could require demolition and reconstruction of almost one kilometre of an elevated viaduct in Vile Parle East after the height of overhead electric wires exceeded the clearance permitted by the Airports Authority of India in the airport funnel zone. The mismatch, of about two point five metres, has halted work on the stretch despite most civil construction being complete. The authority estimated that if no technical remedy is found, work valued at Rs two point five billion (bn) may have to be redone, adding to delays. The short extension was originally scheduled to open in 2021 and has missed several deadlines, and officials indicated it is unlikely to open in the financial year 2026-27. The project is a three point four-kilometre extension of Metro Line 7 from Andheri East to Chhatrapati Shivaji Maharaj International Airport and will connect with the underground Metro Line 3 to provide a direct link for commuters. The elevated section affected includes the Airport Colony station, viaduct and ramp. MMRDA officials said the problem relates to the additional height required for the overhead electric equipment to operate the metro, which was not factored into the original design when no-objection certificates were issued in 2022. Construction on the Vile Parle East stretch advanced after permissions were granted, and the issue was flagged in 2025, prompting a pause and requests for revised clearance from the Airports Authority of India. The civil consultant consortium of Systra, CEG and SMCIPL holds differing positions, with the consultant denying responsibility and the authority yet to permit the extra height. MMRDA data showed that by February 2026 the entire elevated viaduct was complete and 95 per cent of the elevated ramp had been constructed, with the Airport Colony station substantially finished. The alignment comprises approximately two point five kilometres of underground track and 940 metres of elevated alignment. A questionnaire sent to the Mumbai Metropolitan Region Development Authority on August 19 elicited no response.