Mumbai Metro 7A construction resumes, Airports Authority of India clearance awaited

Mumbai Metro Line 7A construction has resumed despite a 2.5-metre height breach near the airport, with the MMRDA awaiting final clearance from AAI.

The Mumbai Metropolitan Region Development Authority (MMRDA) has resumed construction of Metro Line 7A, months after suspending work over a breach of height restrictions in the air funnel zone of Chhatrapati Shivaji Maharaj International Airport (CSMIA), even as it awaits final clearance from the Airports Authority of India (AAI), officials said.

The MMRDA is still awaiting a final decision from AAI regarding height clearance

A design error near Vile Parle East had put a 1-km elevated stretch of the 3.4-km corridor at risk of demolition because the height of the overhead wires exceeded the Airports Authority of India (AAI) limits by 2.5 metres.

The MMRDA is still awaiting a final decision from AAI regarding height clearance. However, it has decided to resume construction nonetheless, two MMRDA officials familiar with the metro line’s construction status told HT.

“While the metro line’s height breaches the air funnel, it isn’t significant. A couple of buildings in the neighbourhood are slightly taller. In fact, the trees alongside are taller than the structure we are constructing,” one of the officials said.

An air funnel is a flight path, similar to road lanes, within which an aircraft is expected to remain airborne. There are strict height restrictions for buildings and other structures within an air funnel zone to ensure safe aircraft take-offs and landings.

Earlier this year, MMRDA officials had said they were facing a potential loss of around ₹250 crore if a relaxation from AAI, which they had been awaiting since January 2024, did not come through. MMRDA had secured a no-objection certificate (NOC) from AAI in March 2024. However, its engineers reportedly failed to account for the additional height clearance required for the overhead electrification (OHE) wires that power the trains, resulting in a 2.5-metre breach.

In the last couple of months, MMRDA officials have met and spoken to their counterparts at CSMIA, AAI and the Ministry of Civil Aviation, said the official quoted earlier. A team from CSMIA had also visited the project site to assess potential safety risks. “The airport team informed us that they have installed an upgraded version of the Instrument Landing System. Hence, it should not be an issue, and it will not infringe on the aircraft movements,” the official said.

An Instrument Landing System is a ground-based radio navigation system that provides an aircraft with horizontal and vertical guidance to safely approach and land on a runway. The upgraded version allows aircraft to approach the runway with higher precision and in significantly lower visibility.

MMRDA officials told HT that Mumbai International Airport Limited (MIAL), which operates CSMIA, sent a proposal to the central government outlining its views on the matter over a month ago. Now, AAI has to formally decide whether to grant MMRDA a relaxation from height restrictions as a special case.

Another official in the know said that the 3.42-km route would take about another year and a half to be ready, which means March 2028 is the earliest passengers can expect operations to begin. Certain challenges have arisen in constructing the underground station at Terminal 2, but these are also being resolved, the official said.

Metro Line 7A is an extension of Metro 7 (Gundavali–Dahisar East) and Metro 9 (Dahisar East–Mira Bhayandar). The project cost of this partially underground line is estimated at ₹812 crore.