§ 139
Return & Assessment
Return of income
Income-tax Act, 1961
Requires every person whose income exceeds the basic exemption limit (and certain others) to file a return of income by the due date — usually 31 July for non-audit cases and 31 October for audit cases. Also covers belated, revised and updated returns.
Plain-language summary — not the official text. Refer to the bare Act and confirm with a professional for your specific case.