Tax deduction at source on arrears must be recomputed and fully recovered, non-compliance attracts interest and penalties. Employers must deduct tax at source under section 192 from salary and arrear payments per Circulars 756 and 757; drawing and disbursing officers must recompute and immediately recover full tax on arrears arising from pay revision and remit it to the Central Government by 20 November 1997, non-compliance attracting interest under section 201(1A) and other penal consequences.