Rate of TDS on Payments of Winnings from horse race under section 194BB of Income Tax Act, 1961 is 30% plus surcharges, education cess and secondary higher education cess. Tax is to be deducted at the time of making payment. Thus if the prize is paid in installments, the deduction of tax shall be made at the time of each installment. (However keep in mind that the exemption limit of Rs.5000/- is per winning and not per payment).
Reference: Section 194BB of the Income Tax Act, 1961
Winnings from horse race
194BB. Any person, being a bookmaker or a person to whom a licence has been granted by the Government under any law for the time being in force for horse racing in any race course or for arranging for wagering or betting in any race course, who is responsible for paying to any person any income by way of winnings from any horse race in an amount exceeding five thousand rupees shall, at the time of payment thereof, deduct income-tax thereon at the rates in force.