NRIs must file tax returns if income in your home country is more than $ 300 pm. This means that if one has property in India from which you receive rent of say Rs.15,000 and have fixed deposits that return Rs.5,000 pm and earn dividends you must file tax returns as your total annual income in India becomes over Rs.250,000.
You must also remember and take into account various aspects, or consult your tax advisor or accountant as interest on NRO accounts are fully taxable and mandatory.
The deadline for filing tax returns is now August 31, 2015. You know of course that you may file your tax returns online on the IT Department e-filing portal, post your documents to the IT department, or file through one of the numerous tax agents, who will of course charge you a service fee.