In a brief technical study of an old defence airstrip in Thane, the Airports Authority of India has indicated that an airport can be made in this timeframe.

To be sure, the ministry has asked for a proper feasibility study to be carried out of this approximately 1,600-acre area near Kalyan in Thane district where a runway of about 6,000 feet exists and additional land can be acquired without much difficulty.

The idea, sources said, is to build a basic airport within a year so that traffic can be diverted from Mumbai until the Navi Mumbai Greenfield airport comes up.

The airstrip, however, is under defence control, so what is being planned is a civil enclave.

Sources said the ministry will soon start consultations with the Defence Ministry on the proposal but before that it needs to resolve a key technical issue. Given that the GVK consortium will lose revenue if traffic gets diverted to this third airport, the ministry will need to hold consultations with the consortium before arriving at any decision.

The consortium already enjoys the first right of refusal for the Navi Mumbai airport and should technically be given some benefit from this project too. While these issues need to be sorted out, the big picture is that the Navi Mumbai airport will take at least another five years to come up given that the bidding process is yet to start.

According to plans already afoot, the ministry hopes that congestion in all major airports will ease by 2008 when the second runway in Delhi would be ready and new airports get operational in Hyderabad and Bangalore.

Mumbai, however, will continue to face this problem as no second runway is possible at the existing airport.

A third airport at Thane presents an interim solution. Officials feel this airport may be closed when Navi Mumbai airport comes up.

It is 32 km from the existing airport, same as Navi Mumbai. Since a technical clearance was obtained for Navi Mumbai from the International Civil Aviation Organisation, a project with similar technical parameters can get the ICAO nod soon.

While the Civil Aviation Ministry says that the proposal is still at a very preliminary stage, sources say that a decision will have to be taken soon if the main purpose of decongesting Mumbai airport in 2008 has to be met.