On which date was the Mumbai Metro's Blue Line 1 officially inaugurated?

Q. On which date was the Mumbai Metro's Blue Line 1 officially inaugurated?
Answer: June 8, 2014
Notes: Mumbai Metro Blue Line 1 was inaugurated on June 8, 2014. It is the first metro line in Mumbai and the fifth rapid transit system in India, serving the Mumbai Metropolitan Region, including cities such as Thane and Navi Mumbai.