S. 143(1): Assessment-Intimation-Employees’ contribution to Provident Fund and ESI-Delay in deposit-Adjustment while processing return under section 143(1)-Valid-Processing of return-Intimation dated 31-3-2021 communicated by e-mail on 1-4-2021-Not barred by limitation-Prima facie adjustment-Incorrect claim apparent from return-Adjustment based on tax audit report-Valid-Prima facie adjustment-Prior intimation through e-mail-Compliance with principles of natural justice. [S. 36(1)(va), 143(1)(a)]