As per section 288B, tax payable by the taxpayer or tax refundable to the taxpayer shall be rounded off to the nearest multiple of ten, following points should be kept in mind while rounding off the tax:
First any part of rupee consisting of any paisa should be ignored.
After ignoring paisa, if such amount is not a multiples of ten, and the last figure in that amount is five or more, the amount shall be increased to the next higher amount which is a multiple of ten and if the last figure is less than five, the amount shall be reduced to the next lower amount which is a multiple of ten; and the amount so rounded off shall be deemed to be the tax payable by the taxpayer or refundable to the taxpayer.
Illustration for better understanding
If the tax liability or refund due to Mr. Keshav is Rs. 2,52,844.99, then first paisa shall be ignored, (i.e., 0.99 paisa shall be ignored) and the remaining amount of Rs. 2,52,844 shall be rounded off to Rs. 2,52,840 (since last figure is less than five). If the tax liability or refund due is Rs. 2,52,845 or Rs. 2,52,846.01, then it shall be rounded off to Rs. 2,52,850 (since the last figure is five or above).
Source: Income Tax India’s Official Website https://incometaxindia.gov.in/Pages/default.aspx