TDS under Section 51: obligation to deduct on payments to specified government bodies, PSUs, and registered scrap buyers. The notification appoints the date from which specified persons must deduct tax at source on payments to suppliers: government-established authorities and boards with majority participation, government-established societies, public sector undertakings, and later included registered recipients of metal scrap. It also sets carve-outs excluding certain defence authorities, excludes supplies between public sector undertakings, and generally excludes supplies between specified persons except for the metal scrap recipient category; subsequent notifications amended these scope and exclusion provisions.