The dust storm followed by rainfall on Thursday evening caused technical glitches in the signalling system and disrupted Metro operations on the red line which connects Dilshad Garden with Rithala.
The Metro service was badly affected after the dust storm began around 5.15pm as the track circuit dropped, said Anuj Dayal, chief spokesperson of Delhi Metro Rail Corporation (DMRC). This caused bunching of trains in both directions as the frequency of trains was high as it was peak hours, he said.
"Track circuit generally drops during dust storm and rainfall. So trains had to be run manually at a restricted speed," Dayal added.
A track circuit is an electrical device used to detect the absence of a train on rail tracks and is used to inform signallers and control relevant signals.
Normalcy was restored within half an hour, a Metro official said.
Sidhant Kapoor, a commuter, who boarded the train at Dilshad Garden around 5pm reached Barakhamba Road Metro station after 6pm.
He said, "I was stuck at the Jhilmil station for quite some time. The train was moving at a very slow speed and when it reached Jhilmil, it started raining. The train stood there for quite some time. Even its air conditioning and lights stopped working."