 Any assessee (Company or firm or a person) who's income exceeds the maximum amount which is not chargeable to tax is required to file return u/s 139(1) within the due date.Currently, the maximum amount not chargeable to tax (basic exemption limit) for individuals is Rs.2,50,000 for below 60 years, 3,00,000 for 60 years to 79 years and 5,00,000 for 80 years and above.