National Common Mobility Card is an open-loop, inter-operable transport card conceived by the Ministry of Housing and Urban Affairs under Prime Minister Narendra Modi's ‘One Nation, One Card' vision. It was launched on 4 March 2019. From Wikipedia
The 12-km Aqua Line from Aarey Colony to Bandra Kurla Complex will open with 10 stations, marking a major milestone for the city's transit system.