The accused, identified as Shahidoor Saiyad Ali Mandal, was arrested from Sion yesterday with 22 kg of marijuana in his taxi, in a trap laid by Anti-Narcotics Cell (ANC) of the Mumbai Police in Sion, they said.
Anti-Narcotics Cell's Azad Maidan unit carried out the arrest.
"We are investigating the source of the contraband and trying to find out about the accused's customers as well," Deputy Commissioner of Police (ANC) Shivdeep Lande said.
An offence has been lodged against Mandal under relevant sections of the Narcotic Drugs and Psychotropic Substances Act.