Under mounting pressure from pending AGR dues from the 2015 spectrum auction and spectrum fees, Vodafone Idea (Vi) has proposed to the government that it surrender some spectrum acquired before 2021. The telecom firm, jointly owned by the UK's Vodafone Plc and the Aditya Birla Group, outlined this plan in a letter to the Department of Telecommunications (DoT) secretary, Neeraj Mittal, on March 10, according to a report by The Economic Times (ET).