The Central Industrial Security Force (CISF) has returned a bag containing jewellery worth Rs.4 lakh to the person who mistakenly left it behind at the Chandni Chowk Metro Station, an official said on Sunday.A CISF official on Saturday evening noticed an unclaimed bag at the X-ray scanning machine at Chandni Chowk Metro station.The official segregated the bag for a second scanning and found that it contained jewellery worth about Rs.4 lakh, a senior official said on Sunday.A Delhi-based jeweller, identified as V. Khandelwal, later returned to the place to claim the bag from Metro authorities, which was duly returned following verifications."Khandelwal said he got busy on a phone call and in the meantime forgot to collect the bag after he put it on the X-ray scanner," the official said.