The factory used to speed-post heroin consignments to London, Denmark among several other places, Senior Superintendent of Police Neelesh Anand Bharne said, adding, the factory has been sealed.
On a tip-off, police arrested one Harjinder who came here to speed-post the drug consignment.
Around 10 grams of heroin were seized from his possession, he said.
On the arrested persons' information, police raided the factory and seized 5 grams of heroin worth Rs 50 lakh in the international market.
Police said Harjinder has been booked under NDPS (Narcotic Drugs and Psychotropic Substances) Act and sent to jail.