Income tax return filing is mandatory for Indian citizens if their income in a financial year is more then the basic exemption limit. Under the old tax regime, the basic exemption limit is Rs 250,000 for an individual, Rs. 300,000 for senior citizens and super senior citizens are exempted up to Rs 500,000. Rs 250,000 is the basic exemption limit under the new tax regime as well, irrespective of taxpayers' age.