Bhopal (Madhya Pradesh): The biggest challenge facing the Chief Information Commissioner (CIC) and three state information commissioners, who took the oath of office on Tuesday, is to clear the backlog of 16,500 second appeal cases filed under Right to Information (RTI). Vijay Yadav has been sworn in as CIC, while Vandana Gandhi, Umashankar Pachauri, and Omkar Nath have taken the oath as state information commissioners.