Vice Chairman of NITI Aayog Arvind Panagariya has said that history will judge Prime Minister Narendra Modi's demonetisation decision as a masterstroke to curb black money.<br/><br/>In an interview to DD News, Dr Panagariya said, discretionary powers of tax officers should be curbed and tax exemptions minimized to simplify the taxation system. He said, this will help widen tax base and increase tax collection.