Mumbai's most expensive Metro line, the underground Metro line 3, will connect Colaba to Andheri east through the commercial hub of Bandra-Kurla Complex by 2021.
The tunneling work on the section has been going on for close to 130 days.
The electrified track of the Metro will be laid down once the tunneling is complete. 80 percent of the tunneling work of the entire route is expected to be completed by 2019. The line will only be fully operational in 2021.