Mumbai Customs have arrested two passengers for alleged possession of 8.5 kg of hydroponic weed worth Rs 8.56 crore at the international airport, an official said on Monday. Officials of the Airport Commissionerate intercepted two passengers, who had landed at the Chhatrapati Shivaji Maharaj International Airport from Bangkok on Saturday, he said.The contraband was concealed inside their trolley bag, the official said, adding that a case under provisions of the Narcotic Drugs and Psychotropic Substances Act has been registered against the duo.