Based on a tip-off that ganja was being supplied in and around Vettakarainpudur, a police team was keeping vigil since early today and noticed a person moving in a suspicious manner, police said.
On searching him, police found 30 kg of ganja in several packets in the man's bag, they said, adding, the man has been identified as Dharmaraj of the same area.
Police said interrogation revealed that he used to bring ganja from Theni and was supplying it to students.