“We’re inviting global tenders for the integrated development and construction of underground shopping in the station area for the corridor in another 10 days,” said P R K Murthy, Chief of Transport and Communication Division of the MMRDA.

He added that agencies in Japan are keen to assist MMRDA since they have successful underground Metro corridors in Tokyo with shopping areas that fetch additional revenue for the transport authorities. The consultant will provide a design of the construction and also give estimates of the revenue the commercial exploitation could potentially generate.

The 19.5 km underground route, that is estimated to cost around Rs 12,000 crore, is likely to be funded by Japan Bank for International Cooperation (JBIC).

According to Metropolitan Commissioner Ratnakar Gaikwad, since the viability gap fund for the third Metro corridor is huge, commercial exploitation of the underground section is essential to make the Metro corridor self-financed. Globally, commercial exploitation of underground stations has not been successful.

Whether it could be successful and accepted in Mumbai’s conditions, Gaikwad said: “International expertise is sought along the line of Metro rails in Tokyo and Toronto where authorities have had good integrated development in the station area with shopping and other commercial exploitation being highly successful”. He added that Metro system in Tokyo has gone three levels below the ground level for commercial exploitation despite being located in a coastal area like Mumbai.