The four arrested accused include a national of Nigeria and two of Afghanistan, DCP (Special Cell) PS Kushwah said.
"A total of 29 Kg of fine quality heroin valued at around Rs 125 crore has been recovered from the arrested accused.
"The entire network of international narco-syndicate originated from Afghanistan and terminated in Europe through Nigerian traffickers with its trail through Pakistan, J&K and Delhi as a transit point," he said.
Special Cell was working on information that some persons from Kashmir have been visiting Delhi and supplying consignments of heroin to people of Afghan origin who had migrated to India. The information had further disclosed that these consignments were further routed through some Nigerians and Afghan nationals, he said.
Based on specific input, a special team of the police caught a Srinagar resident, Jehangir Ahmad, from Pashim Vihar area here recovering 11 Kg heroin from him on March 26. During interrogation, he disclosed that the heroin was given to him by one Kashmiri and it was to be delivered to an Afghan citizen Gorbachan Singh who had been living in Delhi for the past one year, the officer said.
Further, on March 29, Gorbachan was caught from Vikas Puri and one kg heroin was recovered from his possession, the officer said.
Another accused, Afghanistan national Mumtaj, was arrested on March 31. He told the police that he received directions from Pakistan and Afghanistan to receive heroin in India and to deliver the same to some specific people.
His passport details showed that he travelled to Pakistan before coming to India.
"He admitted supplying a huge consignment to one Nigerian on the direction of a person Azlam who is based in Pakistan. He also revealed that the heroin was manufactured in Jalalabad, Afghanistan, later shipped to Azlan, who further pushed it to J&K," Mr Kushwah said.
The accused receiver of the heroin -- Nnadi -- was arrested from Najafgarh and one Kg heroin was recovered from him on April 6. He also led to recovery of another 15 Kg of heroin from his room in Nawada in Dwarka here, the officer said.
"He disclosed that he worked for an international syndicate operated by some Nigerian nationals for supplying the heroin from Delhi to Europe and Middle East countries," he said.
Nnadi was previously arrested by Narcotics Control Bureau in 2017 and convicted for seven years. He came out of prison in 2014 and restarted drug trafficking, the officer said.