The man, identified as Pankaj, was held yesterday by the metro security officials who found live cartridge after screening his bag at the Noida metro station at sector 15, DSP Vijay Dul said.
He was later handed over to the police last night, Dul said.
"The man put his bag in scanner and stood in the queue to board the train. The scanner detected live cartridge in the bag and the CISF team nabbed the man," he added.