So far as IT assessment orders are concerned, they cannot be reopened on the scope of income escaping assessment under s. 147 of the Act of 1961 after the expiry of four years from the end of the assessment year unless there be omission or failure on the part of the assessee to disclose fully and truly all material facts necessary for the assessment. As already mentioned, 'this cannot be said in the present case. The appeal is consequently allowed; the judgment of the High Court is set aside and the impugned notices are quashed.