Withholding on contractor and lottery payments required; payers must deduct tax at prescribed rates unless a certificate directs otherwise. Section 194B requires tax deduction at source on lottery and crossword winnings above the statutory threshold at the time of payment, with a transitional exclusion for payments before the commencement date. Section 194C requires payers to deduct tax from sums paid to contractors and from non-individual contractors to subcontractors for work or supply of labour, subject to an exemption for low-value contracts and to certificates from the Income-tax Officer authorising lower or no deduction.