The bag was detected around 1 am by a Central Industrial Security Force staffer.
An unattended bag triggered panic on Friday at the Delhi airport on the suspicion of containing RDX, but officials later said it was claimed by a passenger who had forgotten it outside the Terminal-3.
The bag contained a laptop, its charger, some toys and clothes, they said, declaring there was no RDX or any other explosive in the bag, which was opened in the presence of the claimant.
The passenger, who was identified as Shahid Hussain by officials, contacted police authorities after over 16 hours of losing his bag.
He said he was a part of a group of four people and had forgotten the bag outside the Indira Gandhi International airport's Terminal-3 after he arrived from Mumbai on a SpiceJet plane, they said.
The passenger, the officials said, told a joint investigation team of security officials that the bag contained a laptop, among other items.
Hussain said he had forgotten his luggage at the airport as the group had a number of bags, they said.
The passenger was taken to the isolated area at the IGI airport where the black coloured trolley bag was kept inside a total containment vessel (TCV) or a thick metal sheeted bomb defusing container, the officials said.
The man has been handed over to the police for further probe and to unravel the entire sequence of events which prima facie looks to be a case of oversight by the passenger and his group, they said.
"Hussain, a resident of Ballabhgarh, landed in Delhi at 12.30 am on Friday from Mumbai in a Spicejet plane. He was accompanied by his three friends. Hussain works in a steel structure company and left he unintentionally," a senior police officer said.
The entire security paraphernalia at the sensitive airport went into a tizzy after initial inputs suggested that the bag could be containing RDX.
What added to the suspicion was that the place where the bag was spotted was in a "dark zone" outside the arrival terminal, where there is little CCTV coverage.
The explosive vapour detector somehow indicated the presence of RDX and hence, all security drills like isolating the suspicious bag and restricting passenger movement was undertaken, officials said.
The bag was detected around 1 am by a Central Industrial Security Force (CISF) staffer and was subsequently kept in an isolated zone with a joint team of CISF, the bomb experts of the National Security Guard and forensics keeping it under observation.
"The bag was removed with the help of the CISF and shifted to another place. It has not been opened yet. It seems like there are some electric wires inside it. We have increased the security of the airport premises," Sanjay Bhatia, deputy commissioner of police (airport), had said soon after the incident was reported.
Preliminary inputs suggested the contents of the bag could be RDX, the sources said. It was checked by an explosive detector and a sniffer dog.
CISF Special Director General (airport sector) MA Ganapathy, however, had said it was "premature" to say the explosive is RDX grade.
"It can be any material and the initial inputs can be false. To say it is RDX at this point of time is highly premature. We should wait for the final assessment report," Mr Ganapathy had told PTI.
Research Department Explosive, acronymed RDX, is a deadly non-smelly explosive and has been used by terrorist elements in the past to create mass casualties.
Officials said in the morning that the suspected explosive has been put under observation for the next 24 hours and something certain can be said only after that.
In July this year, a piece of cargo at the Vadodara airport was suspected to containing RDX. It later turned out to be a consignment of pellets and air guns, an official in the security establishment said.
Giving details of Friday's incident, Delhi Police officials said a call was received around 1 am, following which the bag was found at arrival gate number two of the terminal.
The discovery of the bag caused panic among passengers who were not allowed to exit the terminal for sometime, sources at some airlines said.
Officials said CISF and Delhi Police personnel conducted a complete anti-sabotage check of the airport after which passenger movement was allowed around 4 am.
The CISF and police have stepped up security at the facility in accordance with standard procedure, they said.
Delhi airport has three terminals and domestic as well as international flights operate from the Terminal-3.