Any individual earning more than Basic Exemption Limit i.e. Rs. 2,50,000/- p.a. needs to file tax returns compulsorily, even if the tax is already deducted (TDS) and paid . If you have not filed your returns for past few years, then you could get notice/intimation from the IT department.

If there is a significant reduction in your income from last year, it may cause suspicion and might invite an IT Scrutiny. This is more applicable in case of businesses and traders, because their income is highly volatile. However, in case of salaried people, this does not pose a problem.

If you have filed your returns claiming a high refund in a particular year, there are chances that you might get a scrutiny. This is because you could be asking for a higher amount to be refunded to you. Dues to this, the tax department may want to have a look at your documents and might question things. Similarly, claiming a relief also attracts scrutiny these days.