This case presents two civil appeals to the Supreme Court of India stemming from Special Leave Petitions that contest the High Courts of Delhi and Sikkim's rejection of writ petitions ... by Hero Motocorp Ltd. and Sun Pharma Laboratories Ltd., which argue that the Union of India must honor the 100% excise duty exemption promised in a 2003 Office Memorandum, notwithstanding the enactment of the Central Goods and Services Tax Act, 2017.