India's GST, launched July 2017, replaced a complex web of central excise duty, service tax, VAT, CST, entry tax, and numerous cesses with a unified framework. Nine years on, GST has transformed India's tax landscape — creating a unified national market while building an increasingly automated compliance architecture. ## Four-Tier Rate Structure and Common Products 5% Slab: Packaged food, tea, coffee, medicines, handloom, standalone restaurants, economy air travel. 12% Slab: Processed food, fruit juices, computers, mobile phones, non-AC hotels (₹1,000-7,500/night), bicycles. 18% Slab (revenue workhorse): Most services including IT services, AC restaurants, hotels above ₹7,500/night, electronics, cement, steel, paint. 28% Slab: Luxury goods, premium vehicles, aerated beverages, tobacco base rate, premium 5-star hotels. 28% plus Cess: Luxury cars (15-22% cess), tobacco products (71-204% cess). ## CGST/SGST vs IGST — The Federal Split For intra-state transactions: GST splits equally — CGST (50%) to Centre and SGST (50%) to State. For inter-state transactions: Full IGST to Centre, which distributes to destination state. An 18% intra-state transaction = 9% CGST + 9% SGST. The same 18% inter-state transaction = 18% IGST. Both result in the same total tax for the buyer — the split only matters for businesses claiming ITC. ## Input Tax Credit and E-Invoicing ITC prevents cascading taxation: each registered seller claims credit for GST paid on inputs, paying only the net GST on value added. ITC is blocked on motor vehicles (except transport businesses), food/beverages (except hospitality), and personal consumption items. E-invoicing is mandatory for businesses with annual turnover above ₹5 crore. Tax invoices must be validated in real-time on the Invoice Registration Portal (IRP), generating a unique IRN and QR code. Invoices without valid IRN are not recognized for ITC claims. E-invoicing data auto-populates GSTR-1, significantly reducing manual filing burden.