A 38.24 km long Colaba-Bandra-Charkop line was proposed as Line 2 in the original Mumbai Metro master plan unveiled by the MMRDA in 2004.
The line's construction was handicapped by the lack of available land for carsheds at Charkop and Mankhurd; coastal regulation zone (CRZ) laws forbade construction on the land that had been selected by the MMRDA.