It is mandatory to file ITR if gross total income of an assessee exceeds the maximum exemption limit
According to the income tax website, till 31 March 2018, there were about 379 million Permanent Account Numbers (PAN) allotted to various entities. Out of these, 369 million or 97.46% PANs were allotted to individuals. But irrespective of the fact that you have been allotted a PAN, it is not mandatory to file an income tax return (ITR) if your income is less than the maximum exemption limit. But it is mandatory to have a PAN card to file an ITR. In FY2017-18, about 67 million returns were filed, which is about 18% of total PAN allotted. Read more to know when one needs to file tax returns.