Employee contribution deduction depends on timely deposit to welfare funds, with strict treatment distinguishing it from employer contributions. Employee contributions collected by an employer for provident fund, superannuation fund, ESI, or other welfare funds are deductible only if credited to the relevant fund on or before the prescribed due date. The older framework treats such sums as business income unless deposited within time, while the newer framework allows deduction only where the employee contribution is deposited on or before the due date for filing the return of income. The rule is strict, and employee contributions are distinguished from employer contributions covered separately under section 43B(b).