State-run BSNL is planning to launch a promotional unlimited wireline broadband plan, that costs less than 1 rupee per GB download cost, for subscribers using up to 300GB data in a month.BSNL Chairman cum Managing Director Anupam Shrivastava said, under this plan, customers can download unlimited Broadband data without bothering about any data limit . BSNL said that if customers use the plan continuously in a month, they can download upto 300 GB data by paying 249 rupees.Mr Shrivastava added that BSNL is the only operator offering lowest per GB data download cost plan, under broadband services in the country.