Demand due intimation order due to IT Dept processing error.

If the TDS data is correct in AIS report, file revised return immediately. The entry might have been missing in original return.

File a revised return immediately 

CPC processing errors under Section 143(1) are more common than they should be. Before choosing a route, identify what the mismatch is.

Log into the e-filing portal, go to e-File > Income Tax Returns > View Filed Returns, and open the intimation PDF. The demand will show which line item the CPC adjusted: TDS mismatch with Form 26AS, disallowed deduction, or arithmetic error.

Route 1 - RECTIFICATION (most common fix): Fastest for pure computational errors. Go to e-File > Rectification Request, select Return Data Correction, and correct the specific field. CPC re-processes without human review in most cases. Revised intimation comes within 30 days.

Route 2 - GRIEVANCE: If CPC wrongly failed to credit TDS shown in Form 26AS, file under e-Nivaran. Include PAN, AY, and the specific error. Works faster for cases where your data is correct but CPC did not pick it up.

Route 3 - REVISED RETURN: Only if you are still within the revised return deadline (December 31 of the AY). If that deadline has passed, rectification is your only path.

Do NOT pay the demand first and contest later. Pay only after rectification is rejected, as voluntary payment can be treated as acceptance of the demand.

This [Section 143(1) intimation and demand resolution guide](https://taxgarden.in/blog/section-143-1-intimation-cpc-processing-demand-refund-india) has the portal steps and common error types covered.