Answer to your question is debatable, as there is no clear guidelines or instructions wherein it has been given that such and such person needs to file return. Although it is clarified that persons whose income falls in taxable slab must file their income tax return.
Advice to file return is purely on understanding of professionals who differ in their opinion as to who should file a return and when one should not.
Many professionals advice that one should file a return only when one's income falls in taxable slab or else not.
While some professional advice that your should file your return irrespective of the fact that your income falls in taxable or exempt slab. Some have even adviced that if you have a PAN, then also you should file your return.
So, going by prudence one should file his return in following cases:
1. Income exceeds Rs. 2,50,000/ 3,00,000/5,00,000 for individual upto 60 years, 60 to 80 years and above 80 years, respectively.
2. If income exceeds the taxable limit but after deductions under section 80C to 80U the income falls below the taxable limit, then also an individual shall filw ITR.
3. If the total income falls below taxable limit and there is no tax liability, but, there is TDS deducted by any party/bank or financial institution, then too an individual must file ITR to claim refund of TDS deducted.
4. If the income is below taxable slab and also there is no tax deduction then one can ignore filing tax return.
Although, it is advisable to file even a NIL tax return, as it may help in future, in case one is looking for securing a personal loan or a home loan from bank or any other financial institution.
Many salaried employee have this concept that if, tax is deducted and deposited on their behalf by the employer and Form 16 issued to them, then, they do not need to do anything. But this is a serious mistake and can invite notice/intimation from Income Tax Department. Earning income and getting the tax deposited was one part, but filing return and reporting one's income to the Income Tax Department is another part. This must be strictly followed.