New Delhi, Feb. 1 -- The budget's biggest, shiniest takeaway: no tax on income up to Rs.12 lakh. Union finance minister Nirmala Sitharaman's announcement was met with much cheer and enthusiastic number-crunching across the country.

Before you pop the champagne, though, there are two points to consider. First, zero tax up to Rs.12 lakh as well as the attractive new tax slabs are only applicable to the new tax regime. At the same time, the old tax regime does remain relevant in some cases.

Second, if your taxable income is Rs.12 lakh, your tax liability is not zero; it is Rs.60,000 (per the new tax slabs). However, it will become zero once the rebate of Rs.60,000 kicks in (it was earlier Rs.25,000).

And if you are salaried (as opposed to...