Metro Rail has issued a call for bids for the 6.8 km extension of Kolkata's Yellow Line, from the Airport to Birati. The Rs. 1,330 crore contract encompasses the construction of Birati and Michael Nagar stations.

This development follows the Airports Authority of India (AAI) granting necessary clearances, including resolving height restrictions for cranes required in the construction process. On July 5, TOI reported that despite previous delays, the project is making progress, with AAI's approval facilitating work outside the airport perimeter.

The Yellow Line, connecting Noapara to Barasat via the airport, is a crucial part of Kolkata’s transit expansion.

The recent bid invitation is for civil construction work on the 6.8 km underground extension. This follows AAI's approval for the use of 18-meter tall cranes for the Airport-New Barrackpore section of the 11.2 km Noapara-Barasat extension and the much-anticipated NOC for work between the airport and Michael Nagar. Discussions are ongoing to resolve the issue concerning the New Barrackpore station, which is near a major runway's flight path.

The Rs 1,330 crore contract includes constructing a 3.6 km metro tunnel and two underground stations at Birati and Michael Nagar. The tunnel will be built using the RCC box-pushing method, avoiding tunnel boring machines, while the Birati station will be constructed using the cut-and-cover method.

The selected contractor will be responsible for designing, procuring, and constructing the tunnel and stations, including architectural finishes and essential infrastructure like firefighting and power supply systems.