Services on the Delhi Metro's Yellow Line between Huda City Centre and Samaypur Badli stations were affected on Monday evening due to "signalling issues", an official said.
The issue was reported at Huda City Centre and was being repaired, he said, adding that the snag occurred around 5 pm.
The Delhi Metro Rail Corporation (DMRC) informed commuters about the delay on social media.
"Slow movement of trains between Sultanpur and Huda City Centre. Normal service on all other lines," it tweeted.
"Repair work is underway at Huda City Centre to rectify the issue. Please allow extra time in your commute. We regret the inconvenience," it said in another tweet.