CHENNAI, DECEMBER 15: The south zone unit of the narcotics control bureau today claimed to have busted a major drug cartel run by a Sri Lankan Tamil duo in southern India with the arrest of seven persons, including the Sri Lankans, and seizure of 29.35 kg of heroin worth Rs 30 crore in the global market.Acting on a tip-off, intelligence officers of the bureau nabbed the seven and seized the contraband on the Tumkur-Sira road on the Bangalore-Pune highway in Karnataka this evening when the gang was about to transfer the drug from a car to a waiting lorry, a press release from zonal director T Rajendran said here tonight.Six packets of the heroin bore Pakistani marking, indicating that the drug was of Pakistani origin, while the rest appeared to have been procured from Mandsaur in Madhya Pradesh, the release said.This is the fourth major drug syndicate busted by the south zone unit this year, he said adding that a total of 108 kg of heroin valued at Rs 108 crore in the illegal market had been seized. Tuesday's seizure was also the third one in the last six months in Karnataka.According to preliminary investigations, Balakrishnan and his brother Rajarathinam had been allegedly operating the drug syndicate from India to Sri Lanka with Bangalore as their base.