Assessment proceedings Income Tax Act, 1961, Section 153(1) Explanation, Sections 139 to 158 The process of assessment commences with the filing of the return or when the return is not filed by the issuance by the Assessing Officer of the notice to file the return under Section 142(1) and it culminates with the issuance of the notice of demand under Section 156. The making of the order of assessment is, therefore, an integral part of the process of assessment. Having regard to the fact that the object underlying the explanation is to extend the period prescribed for making the order of assessment, the expression ‘‘assessment proceeding’’ in the explanation must be construed to comprehend the entire process of assessment starting from the stage of filing of the return under Section 139 or issuance of notice under Section 142(1) till the making of the order of assessment under Section 143(3) or Section 144. Since the making of the order of assessment under Section 143(3) or Section 144 of the Act is an integral part of the assessment proceeding, it is not possible to split the assessment proceeding and confine it up to the stage of inquiry under Sections 142 and 143 and exclude the making of the order of assessment from its ambit. An order staying the passing of the final order of assessment is nothing but an order staying the assessment proceedings. [Auto & Metal Engineers v. Union of India, (1997) 7 SCC 734 (737, 738)]