Section 148 of the Income Tax Act empowers the income tax department to reassess previously filed tax returns. The Assessing Officer (AO) is authorized to select returns for reassessment if specific conditions are met, initiated by a notice under Section 148 concerning income escaping assessment.

In 2021, the Finance Act amended the time limit for reopening cases from six to three years. However, cases involving substantial tax evasion, with income concealment over 50 lakhs, can be reopened up to ten years.

Reasons for issuing a notice under Section 148 include the AO's belief that taxable income may have escaped assessment. A reassessment cannot proceed without valid reasons or justification. The AO must document reasons in writing and cannot reassess previously submitted documents without new information indicating income escapement, as defined under sections 147 and 148.

The authority to issue a notice under Section 148 is held by top officials like the Principal Chief Commissioner, Commissioner, or Chief Commissioner, as per Section 151(1). They need to be satisfied with the AO's recorded reasons for issuing the notice. Alternatively, a senior Assessing Officer with the Joint Commissioner's approval can issue the notice if the AO's reasons are valid.

As per Section 149, the deadline for issuing a notice under Section 148 varies. Notices can be issued within three years from the relevant assessment year if the income evaded is not more than 1 lakh. For concealed income exceeding 50 lakhs, reassessment is possible up to ten years from the assessment year. Once a section 143(3) or 147 assessment concludes, no further action is permissible unless it’s due to failure in filing returns or full disclosure by the assessee.

Upon receiving a Section 148 notice, it’s crucial to respond promptly. Verify the AO’s recorded reasons and request a copy if not provided. If convinced, submit your return or forward a copy if already filed. When filing, ensure all income and expenses are accurately represented. If the notice seems unjustified, you may dispute its validity with the assessing officer or a higher authority.