How 12 Lakhs income is tax free ?

Guys, I have a serious question and I might sound stupid here but still, can someone explain me how 12 Lakhs income is tax free ?

I never understood this thing. Earlier when It was 7 Lakhs, I didn't understood it then too.

So, According to newest tax regime, these are the slabs -

0-4L: 0% 4-8L: 5% 8-12L: 10% 12-16L: 15% 16-20L: 20% 20-24L: 25%

24L: 30%

If we just calculate tax for 12 Lakhs, Standard deduction is 75k so taxable income would be

12L - 75k = 1125000 Rs

and for that, tax would be => 0 +20000 + 32500 = 52500 Rs should be total tax.

But how it is zero ?