Indian authorities seized nearly three tonnes of heroin reportedly worth around $2.7 billion in a major operation at a port in Gujarat state.
Two people have been arrested and several others are being investigated.
Forensic testing is still under way to determine the exact value of the seized drugs, officials said.
The shipment originated in Afghanistan, where it was declared as talc stones.
It was shipped to Gujarat’s Mundra port from Iran. The port is owned by private conglomerate Adani Group. The Directorate of Revenue Intelligence (DRI) said that it received intelligence that a shipment from the Bandar Abbas Port in Iran was suspected to contain narcotics.
It said the intelligence also revealed that the shipment was being imported by a company in the southern city of Vijaywada.
“When our officers detained the consignment and examined it, suspected narcotic drugs were recovered from the containers and the presence of heroin was confirmed,” DRI said in a statement.
Officials said searches have been conducted in multiple cities across India, including the national capital, Delhi, Ahmedabad and Chennai.
“Investigations conducted so far have also revealed the involvement of Afghan nationals, who are under investigation,” the agency said.
According to the United Nations Office on Drugs and Crime (UNODC) Afghanistan is the world’s largest producer of opium. Its opium harvest accounts for more than 80% of the world’s supply.
Opium poppy plants are refined to form the basis for several highly addictive drugs, including heroin.