Rulemaking authority enables government to notify GST rules, including retrospective effect and penalties for contraventions. The Government may, on the recommendations of the Council and by notification, make rules for carrying out the provisions of the Act, including rules for matters required or permitted to be prescribed. The power includes making rules with retrospective effect from not earlier than the date the Act comes into force, and rules may provide that contraventions are liable to a penalty not exceeding ten thousand rupees.