A 19.5 km (12.1 mi) metro line connecting Bandra Kurla Complex with Kanjurmarg via the airport was proposed as Line 6 in the original Mumbai Metro master plan unveiled by the Mumbai Metropolitan Region Development Authority (MMRDA) in 2004.

[2] On 19 October 2016, the Mumbai Metropolitan Region Development Authority (MMRDA), headed by Chief Minister Devendra Fadnavis, approved a plan to build a 14.47 km metro rail line connecting Lokhandwala Complex in Andheri to Vikhroli and Kanjurmarg in the east.

[3] The detailed project report for Line 6 was prepared by the Delhi Metro Rail Corporation (DMRC) in December 2016.

A 1.1 km stretch of Line 6 passes through CRZ areas at the junction of the JVLR and the Eastern Express Highway near Nehru Nagar.

[8] In November 2017, the MMRDA stated that it had reached an agreement with the Brihanmumbai Municipal Corporation (BMC) to build a 2 km section of Line 6 on a common pier with a flyover.

[9] In April 2018, the BMC stated that it was putting work on a proposed crocodile park at Powai Lake on hold until Line 6 was completed.

[10] The MMRDA faced criticism from Lokhandwala and Powai residents at a public consultation meeting held on 21 May 2019.

It continues along the periphery of Powai Lake and terminates at Vikhroli station on the Eastern Express Highway.

[11] The DMRC awarded J Kumar Infraprojects an ₹867 crore (US$100 million) contract for the second package from Lokhandwala to Mahakali Caves in August 2018.

[22] The line will consist of 13 stations from Swami Samarth Nagar in Lokhandwala Complex in Andheri (West) to Vikhroli (East).