(6)Notwithstanding anything contained in the forgoing provisions of this section, where the assessee before the due date for furnishing the return of his income under sub-section (1) of section 139, furnishes to the Assessing Officer a declaration in writing that the provisions of this section may not be made applicable to him, the provisions of this section shall not apply to him in any of the relevant assessment years:[Provided that no deduction under this section shall be allowed to any undertaking for the assessment year beginning on the 1st day of April, 2004 and subsequent years.] [ Substituted by Act 32 of 1994, Section 6, for Explanation (w.r.e.f. 1.4.1993).][Explanation. - For the purposes of this section,-(i)"Integrated Infrastructure Development Centre" means such centres located in the States of the North-Eastern Region, which the Central Government, may, by notification in the Official Gazette, specify for the purposes of this section;(ii)"Industrial Growth Centre" means such centres located in the States of the North-Eastern Region, which the Central Government may, by notification in the Official Gazette, specify for the purposes of this section;(iii)"North-Eastern Region" means the region comprising the States of Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura;(iv)"relevant assessment years" means the ten consecutive years beginning with the year in which the industrial undertaking begins to manufacture or produce articles or things.]