A planning error on Mumbai’s Metro Line 7A could force the demolition and reconstruction of nearly 1 km of an elevated viaduct in Vile Parle East, with the height of overhead electric wires exceeding the clearance permitted by the Airports Authority of India (AAI) in the airport funnel zone, authorities said.

The mismatch, involving about 2.5 metres, has brought work on the stretch to a halt despite most of the civil construction being complete. If a technical solution is not found, work worth around Rs 250 crore could have to be redone, further delaying the 3.4-km Metro Line 7A connecting Andheri East with Chhatrapati Shivaji Maharaj International Airport.

The line was originally scheduled to open in 2021 and has already missed several deadlines. The latest issue indicates it is unlikely to open in the financial year 2026-27.

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According to MMRDA officials, the problem concerns the height of the overhead electric equipment required to operate the metro. While the AAI had issued no-objection certificates for the project when permissions were sought in 2022, the additional height required for the OHE was not factored into the design.

The elevated stretch in Vile Parle East, including the Airport Colony station, subsequently progressed. The height issue was flagged in 2025, following which construction was paused and revised permissions were sought from the AAI.

“While we are trying to strike a balance between Systra and AAI, technical issues cannot be solved through compromise. If we do not arrive at a solution, the viaduct may have to be reconstructed,” an MMRDA official said.

The civil consultant for the line is a consortium of Systra, CEG and SMCIPL. According to the MMRDA, Systra maintains that it was not responsible for the error, while the AAI has so far not permitted the additional height required for the OHE.

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The problem has emerged after substantial civil work was completed. MMRDA data showed that by February 2026, the entire elevated viaduct was complete, while 95 per cent of the elevated ramp had also been constructed. Work on the Airport Colony station was also substantially complete.

Line 7A is planned as a 3.4-km extension of Metro Line 7 from Andheri East to the airport. It will connect with the underground Metro Line 3 at the airport, providing a direct link for commuters from the northern suburbs towards south Mumbai.

The line comprises about 2.5 km of underground alignment and around 940 metres of elevated alignment, including the Airport Colony station, viaduct and ramp.

A questionnaire sent to the MMRDA on August 19 seeking its response went unanswered.