AMRITSAR: In a major breakthrough, Amritsar Commissionerate Police has busted a cross-border drug smuggling cartel with links to Pakistan-based handlers with the arrest of seven accused persons and recovered 4.075 kg heroin, 1 kg Methamphetamine— commonly known as ICE, and one 9mm Glock pistol from their possession, said Director General of Police (DGP) Punjab Gaurav Yadav here on Tuesday.