The word assessment as defined under section 2(8) of the Act has a comprehensive meaning and includes all steps and proceedings taken for determination of tax payable and for imposing liability on the assessee. It includes reassessment as well. Therefore, even after the matter is remitted, and an order of assessment is passed, it is referable to section 143 or section 144. Explanation 3 only protects the assessee from levy of interest and confines it when the original order of assessment is passed and not when the modified order of assessment is passed. Even though in a proceeding for remand, the original order of assessment gets effaced, and a fresh order of assessment is passed, or is passed under section 143(3) of the Act in view of the decision of the Supreme Court in Modi Industries, the expression regular assessmen has to be deemed to have been completed on the date when the first order of assessment has been passed and not when the modified order of assessment has been passed. Interest is chargeable up to the date of first assessment order passed by the Assessing Officer. (AY.1992-93)