While one of the passengers was arrested, the second passenger was let off after questioning.
Both of them had disembarked from a plane coming from Bangkok.
Customs officials found a gold bar weighing 854 gm valued at Rs 21 lakh from one Nandkishore Gupta, a resident of Gorakhpur, during frisking.
Gupta was arrested.
Another person was also found to be carrying 674 gm of gold valued at Rs 17 lakh. The person identified as one Pradip Kumar, a resident of Dumdum, was released after questioning.