A retrospective provision in a taxing Act which is for the removal of doubts cannot be presumed to be retrospective, even where such language is used, if it alters or changes the law as it earlier stood. This being the case, Explanation 3C is clarificatory : it explains section 43B(d) as it originally stood and does not purport to add a new condition retrospectively. Relied on  Sedco Forex International Drill. Inc. v. CIT ( 2005 ) 279 ITR 310 ( SC)  

Any ambiguity in the language of Explanation 3C to section 43B shall be resolved in favour of the assessee. Relied on  Cape Brandy Syndicate v. IRC [1921] 1 KB 64 and Vodafone International Holdings BV  v. UOI ( 2012 )) 341 ITR 1 (SC).