The first DEMU train of India with solar powered coaches was launched on 14th July, 2017 at:

The answer is C) Safdarjung Railway Station. The first solar-powered DEMU rake was flagged off from Safdarjung in Delhi on 14 July 2017. Rooftop solar panels on the coaches supplied power for lighting and fans, which cut the load on the train's own traction and auxiliary systems. Treat the exact station as something to verify against the PIB release, since Delhi-area stations are easy to mix up in memory.

Why the others are unlikely: Sarai Rohilla is a major terminus in Delhi, and it is the station aspirants most often pick by habit. New Delhi is the main long-distance station and is not the flag-off point for this event. Delhi Cantt. is a suburban and cantonment station on a different corridor.

Core concept: Indian Railways' push on green energy, including solar power for coaches and rolling stock. This links to Mains GS-III on energy efficiency, renewable energy adoption and sustainable infrastructure.

Trap: Choosing the biggest or most famous Delhi station (New Delhi or Sarai Rohilla) instead of recalling the specific event location.