The gift is free, but the income comes back to you
The gift itself is not the problem. A spouse is a relative, so gifting money or an asset to your spouse is exempt, there is no gift tax on it however large. What surprises people is what happens next. The income that the gifted money or asset goes on to earn, interest on the deposit, rent from the flat, dividends, even the capital gain when your spouse sells it, is not taxed as your spouse's income. Under Section 64 it is clubbed back and taxed in your hands, as the person who made the gift. The rule catches a gift to your spouse under one clause and a gift to your son's wife under another.
This is why the common plan of shifting income into a lower-earning spouse's name by gifting usually does not save any tax, the income simply bounces back to your slab. For an NRI it means that money you gift to a resident spouse who invests it in India produces income that lands on your Indian return, not theirs. The gift is clean, but the income is yours for tax purposes.
The exceptions, and the loan that works
Clubbing is not absolute, and knowing the exceptions is where the planning is. It does not apply where you transferred the asset for adequate consideration, in other words a real sale at a fair price rather than a gift. It does not apply where the transfer is connected with an agreement to live apart. And it does not apply where the relationship did not exist when the income arose, for example an asset given before marriage. The most useful exception in practice is that a genuine loan is not a gift: if you lend money to your spouse rather than give it, on real terms with an intention to repay, the income it earns is your spouse's, not yours, because a loan is not a transfer without consideration. Keeping it a real loan, documented and repayable, is the standard way around clubbing.
Two more points that soften the rule. Clubbing only reaches a spouse, a son's wife, and a minor child, so a gift to a major son or daughter is not clubbed at all, their income is their own. And only the first round of income is clubbed: if your spouse takes the income that was clubbed and reinvests it, the income on that reinvestment is generally treated as your spouse's own, not clubbed again. Under the Income-tax Act, 2025 the clubbing rule is renumbered to Section 99 from FY 2026-27, but for now it is Section 64. A practising CA structures a gift or loan so it does what you intend, and reports any clubbed income correctly.