They said the incident occurred at 6:00 pm when Ankit Awasthi fell before the metro train at the Sikanderpur metro station.
The driver of the metro applied breaks immediately before Awasthi fell before the train. He was admitted to a private hospital where his condition is stated to remain critical, a senior police official said.
"We are investigating the incident to ascertain whether the victim deliberately jumped before the metro train to commit suicide or he accidentally fell on the metro track," he said.
The police is examining the CCTV footage of the platform to confirm it, he added.