India's Central Bureau of Investigation (CBI) has closed a coal scam case against billionaire Kumar Mangalam Birla and a former top bureaucrat that emerged in 2012 after an auditor's report on revenue loss to the exchequer from allocations of coal blocks. The CBI filed the case against Birla and former Coal Secretary P.C. Parakh last year in relation to a block allocated in 2005 to Hindalco Industries, part of the $40 billion Aditya Birla Groupled by Kumar Mangalam Birla. "The evidence collected during investigation did not substantiate the allegations levelled against the persons named in the FIR (first information report filed in the case)," the CBI said in a statement late on Friday.