S. 147 : Reassessment-After the expiry of four years-Change of opinion-Disallowance of expenditure-Exempt income-Return was not filed in pursuance of notice u/s 148 of the Act-No hard and fast rule that the assessee should first file its return pursuant to the notice-Reassessment notice was quashed. [S. 14A, R. 8D, Art. 226]