A 21 km long tunnel under the sea has been proposed for the Mumbai-Ahmedabad high speed rail (HSR) corridor project. As per the detailed project report submitted by the Japan International Cooperation Agency (JICA), most of the corridor is proposed to be on an elevated track except the stretch after Thane creek towards Virar which will go under the sea. The project involves the development of a 534 km long Mumbai-Ahmedabad HSR corridor in Maharashtra and Gujarat at an investment of Rs 988 billion on a DBFOT basis.