Validation of searches: past income-tax searches deemed compliant with amended provisions and not challengeable on specified procedural grounds. Section 6 deems certain prior income-tax searches to have been made in accordance with the amended subsection of section 132 as if those provisions were in force on the date of the search, and prevents questioning those searches before any court or authority solely on the grounds that the officer acted with assistance or that no proceeding under the earlier or principal Income-tax Act was pending when the search was authorised.