Police have seized mephedrone powder, a banned drug, worth Rs 17.5 lakh and arrested three persons in this connection in Navi Mumbai, an official said. The police›s Anti-Narcotics Cell (ANC) laid a trap at the Belapur creek side following a tip-off and spotted the three persons. During checking, the police recovered 175 gms of mephedrone powder, a synthetic stimulant, from their possession, the official from CBD Belapur police station said. The three persons, including two from neighbouring Mumbai and in the age group of 18 to 32 years, were placed under arrest late Tuesday night, he said. They were booked under provisions of the Narcotic Drugs and Psychotropic Substances (NDPS) Act, the police said.