The Narcotics Control Bureau (NCB) Saturday claimed to have made the country's biggest seizure of over 1,800-kg pseudoephedrine kept outside a factory in Greater Noida and arrested three foreigners. The estimated value of the seized chemical, along with about 2 kg of party drugs Cocaine, is around Rs 25 crore, sources in the NCB said. Noida police sources told PTI that the house where the suspects were staying as tenants belongs to an IPS officer, who is presently posted in the Economic Offences Wing in Lucknow. The agency stumbled upon the record haul of the narcotics chemical and stimulant after the grilling of a South African woman who was arrested by them on May 9 from the Indira Gandhi International (IGI) Airport for allegedly carrying 24.7 kg of pseudoephedrine. The woman was first intercepted by the Central Industrial Security Force. "Pseudoephedrine is a precursor used for the manufacture of Methamphetamine, a drug widely used in Europe and South East Asia. "This is the biggest ever seizure of pseudoephedrine in India kept outside factory premises. As per our records, this is the highest ever seizure by any agency," a senior NCB officer said. Usually such large quantities are always found in factories and not in residential or commercial premises, he said. The woman's interrogation led the officials of the Delhi zonal unit of the NCB to a house in Greater Noida from where a total of 1,818 kg of pseudoephedrine and 1.9 kg of Cociane were seized on May 10, the official said. Two Nigerians, a man and a woman, have been arrested from the house apart from the South African apprehended earlier, they said. The arrests were made under relevant sections of the Narcotic Drugs and Psychotropic Substances (NDPS) Act. The Noida police said the foreigners who were living in the house in Sector P4 on rent did not have any verification of their identity done by the local police. "It's required for any foreigner to get their verification done by the LIU (Local Intelligence Unit). They did not get it done. A probe would be carried out to fix responsibility over this lapse and any other lapses," Senior Superintendent of Police Vaibhav Krishna told PTI. He said the NCB had carried out the action in Greater Noida independently and the local police was not involved. Meanwhile, the police sources said efforts were underway to find out how the suspects got the IPS officer's house on rent and for how long they had been living there. The area where the house is located comes under the jurisdiction of Kasna police station.