The timing rule that protects you
A Section 143(2) notice is how the department picks your return apart, and the assessment that follows is made under Section 143(3). The first thing to check is whether the notice was even valid, because there is a strict deadline. The notice must be served within three months from the end of the financial year in which you filed the return. So a return filed in July 2023, which falls in the 2023-24 financial year, could be picked up by a Section 143(2) notice only until 30 June 2024.
That deadline matters because it is a hard cut-off. If a valid Section 143(2) notice was not served in time, the return becomes final, and the department cannot frame a scrutiny assessment at all, a late notice is a fatal defect, not a technicality to be excused. So the first thing to verify on receiving a scrutiny notice is its date against your filing date. If it is late, that alone can end the matter.
Why you were picked, and how far it goes
Scrutiny selection is largely computer-driven, on risk parameters, so being picked is usually about a specific flag, not suspicion of you personally. For an NRI, the classic trigger is a high-value property sale, especially where the TDS deducted, or the figures in your 26AS and the annual information statement, do not line up with the return. So a scrutiny after a property sale is common and often about reconciling the sale and its TDS, not a fishing expedition.
How far the scrutiny can go depends on its type. A limited scrutiny is confined to the specific issue it was opened for, the property sale, say, and the officer cannot travel beyond that issue into your whole return without getting approval to convert it into a complete scrutiny. A complete scrutiny is open to your full return. Knowing which you are in tells you the scope of what you need to explain. A practising CA checks the notice's validity against the deadline, identifies the flagged issue, and responds with the reconciliation and evidence the officer needs, keeping a limited scrutiny limited.