The CPIM has urged the Prime Minister to explain in Parliament how the murky affair of 2G spectrum scam was allowed to go on for so long. In a statement issued in New Delhi today the party said the report of CAG on the issue of licenses and allocation of 2G spectrum had confirmed what has been in public knowledge for long. Party Leader Sitaram Yechury strongly advocated for prosecuting the former IT Minister A.Raja and guilty officials and also called for immediate steps to undo the damage and recover the lost revenue.