It exemption on gift donation

gift is to be issued from Tax paid income, and it does not reduce your tax liability.

again the income of such amount in hand of wife will be clubbed to your taxable income, 

It is not possible to reduce Taxable income by giving gift.

I mean If you gift any amount to anybody, it will not be reduced from your taxable income.

You have to pay Tax on entire 4 lakhs.

There is no monetary limit for Gift.

For gift you should have Gift Deed as supporting document.

If want to do Taxplanning you have to transfer (Not Gift) Income Generating Asset, but not income.

By gifting Tax paid Income Also possible to do Taxplanning by applying Sec 27 or Sec 64(1).

And also possible to do Tax planning by using Capital Gain Chapters