49. Substituted by the Direct Tax Laws (Amendment) Act, 1987, w.e.f. 1-4-1989. Prior to its substitution, sub-section (4) was substituted by the Finance Act, 1968, w.e.f. 1-4-1968 and amended by the Taxation Laws (Amendment) Act, 1970, w.e.f. 1-4-1971.