Income Tax is a tax imposed on individuals or entities that varies with respective income or profits. Taxation rates may vary by type or characteristics of the taxpayer. The rate may increase as taxable income increases.
It is always advisable to do planning in advance including planning for investments and other income items to avoid last-minute rush during filing returns.
If you are not aware of proper exemption options available then you will have to pay the entire tax depending on your declared income.
As per the budget for 2019, Individual taxpayers having a taxable annual income up to Rs. 5 lakhs are eligible for full tax rebate U/S 87A, so they need not pay any. But returns (ITR) have to be filed.
The government in its budget has increased the standard deduction to Rs.50 thousand in the last budget.