Operations at the Delhi airport largely remained unaffected even as power supply to six states was hit early this morning due to the failure of Northern Grid. "As soon as there was a disruption in power supply, all our essential services like flight arrival and departure, check-in, baggage handling, aerobridge services were shifted to our back-up system. So all these operations remained normal", an airport spokesperson said.

"We have one of the best DG (Diesel Generating) back-up system of the world. However, there might be some disruption in our non-essential services", he added.

There were reports of air conditioning not functioning in Terminal 1D and some portions of Terminal 3. Also, there was no power in some retail outlets at the airport.

"Overall ninety-five percent of our services remained unaffected", a spokesperson said.