Officials said the arrested foreigners include a Bolivian woman and a man, and a Nigerian and a South African nationals.
The two Indians, both women, hail from Manipur.
"We have arrested six people, including four foreigners, as part of our crackdown against international drug cartels operating to and from the country," NCB Zonal Director (Delhi) Madho Singh told PTI.
All the accused have been arrested under the provisions of the Narcotic Drugs and Psychotropic Substances Act (NDPS), he said.
Also Read
They said Gradega was coming in from Ethiopia and on her tip off two Manipuri women, Lhingpichang alias Shilpa (28) and S Khan alias Joyce Karoung, were later arrested as they were reportedly the recipients of the drug consignment.
Further, information from the Bolivian lady led to the arrest of the Nigerian identified as Odonga C Stephen (38), they said.
In the second incident, the sleuths arrested the Bolivian man identified as S J Fernando who had allegedly swallowed 50 drug-filled pills before arriving in India.
In the third incident, the NCB arrested the South African man, Franklyn R Zodwa, as he was allegedly trying to send a drugs parcel containing 440gms amphetamine to Australia from a post office here.
The NCB nabbed Zodwa based on inputs about his activities in a previous case, the officer said.
The three drug racket involve trade of contraband estimated to be worth about Rs 20 crore, the officer added.
Disclaimer: No Business Standard Journalist was involved in creation of this content