Tax on online gaming/

If you receive money from winning the online games, it will be taxable under the caput Income from other sources. The income will be taxable at the plane rate of 30% which after adding 4% cess will amount to 31.2%.Incomes from next sources come under this category:

Lottery
Crossword Puzzle
Races including Equus caballus races
Card games and other games of any sort
Gambling or betting.

If the Prize money exceeds Rs 10,000, then the winner will receive the prize money after the deduction of TDS @31.2% u/s 194B.It does not matter whether the income of the winner is taxable or not. The prize distributor is liable to deduct tax at the time of payment.
even so If the Prize money does not exceeds Rs 10,000, then the winner, itself, will take hold to pay the tax to the Govt.

No deduction under section 80C to 80U or any other deduction/allowance is allowed from such income. The Benefit of basic exemption bound and income tax slab rate is also not applicable to this income. The entire amount received will be taxable at the plane rate of 31.20%.