Which Indian Metro has bagged ISO rating for energy efficient management, recently?
[A]Mumbai Metro
[B]Chennai Metro
[C]Delhi Metro
[D]Kolkata Metro

Delhi Metro
The Delhi Metro Rail Corporation (DMRC) has become the first ever Metro system in the country to be certified with the prestigious ISO 50001:2011 (EnMS) rating for efficient energy management. The ISO 50001: 2011 Energy Management System (EnMS) is a very recent ISO standard on energy management. It specifies requirements for establishing, implementing, maintaining and improving an energy management system, whose purpose is to enable an organisation to follow a systematic approach on achieving continual improvement of energy performance, including energy-efficiency, energy use and consumption. The Delhi Metro is now in the process of getting all the under-construction stations on Phase 3 to be certified as per ISO 50001:2011 standards.