New Delhi, July 31 -- With the 31 July Income Tax Return (ITR) filing deadline here, millions of taxpayers are either rushing to submit their returns or hoping for a last-minute extension. But beyond the annual compliance exercise lies a question many taxpayers overlook: Does earning the same income mean paying the same amount of tax?

The answer is no.

India's income tax system is progressive - higher incomes are taxed at higher rates. Yet final tax liability depends not just on how much a person earns, but also how that income is earned. Salary, pension, professional income and business income are governed by different rules on deductions, exemptions and expense claims, often resulting in vastly different tax outgoes.

Consider four ta...