MODULE III: GST LAW AND RETURN

Unit 1: Constitutional & Structural Architecture of the Dual GST Model

1.1 The Dual GST Framework and Constitutional Enablement

Enacted through the landmark Constitution (101st Amendment) Act, 2016 and implemented nationwide on July 1, 2017, the Goods and Services Tax (GST) dismantled India's fragmented indirect tax regime, subsuming 17 central and state levies (Central Excise, Service Tax, State VAT, Entry Tax, Luxury Tax, Entertainment Tax) into a unified, destination-based, multi-stage value-added tax system under the motto of "One Nation, One Tax, One Market."

Because India is a federal polity, Parliament adopted a Dual GST Model where both the Union Government and State Governments concurrently levy tax on a shared tax base under Article 246A of the Constitution:

• Central Goods and Services Tax (CGST): Governed by the CGST Act, 2017. Levied and collected by the Central Government on intra-state supplies of goods and services.
• State Goods and Services Tax (SGST): Governed by respective State GST Acts (e.g., Kerala SGST Act, 2017). Levied and collected by the State Government on intra-state supplies occurring within its territory.
• Union Territory Goods and Services Tax (UTGST): Governed by the UTGST Act, 2017. Levied on intra-state supplies within Union Territories without legislatures (Andaman & Nicobar Islands, Lakshadweep, Dadra & Nagar Haveli and Daman & Diu, Ladakh, Chandigarh).
• Integrated Goods and Services Tax (IGST): Governed by the IGST Act, 2017. Levied by the Central Parliament under Article 269A on all inter-state supplies of goods and services, as well as on imports into the territory of India. IGST is apportioned between the Union and the destination State.

1.2 Inter-State vs. Intra-State Supply Rules

Determining whether a transaction attracts CGST + SGST or IGST depends on the relationship between two statutory coordinates: the Location of the Supplier (LOS) and the Place of Supply (POS) determined under Sections 10 to 13 of the IGST Act:

Unit 2: GST Registration Framework: Thresholds & Digital Workflow

2.1 Statutory Threshold Limits for Mandatory Registration [Section 22]

Under Section 22 of the CGST Act, every supplier is liable to be registered in the State or Union Territory from where they make taxable supplies if their Aggregate Annual Turnover (AATO) in a financial year exceeds the prescribed statutory threshold:

• Exclusive Suppliers of Goods (Normal Category States): Threshold is ₹40 Lakhs (under Notification No. 10/2019-Central Tax). Applicable in major states (e.g., Kerala, Tamil Nadu, Maharashtra, Karnataka, Uttar Pradesh).
• Suppliers of Services & Mixed Suppliers: Threshold is ₹20 Lakhs across Normal Category States.
• Special Category States (Article 279A):
  • Threshold of ₹10 Lakhs (Goods and Services): Manipur, Mizoram, Nagaland, and Tripura.
  • Threshold of ₹20 Lakhs (Goods and Services): Arunachal Pradesh, Meghalaya, Sikkim, Uttarakhand, Puducherry, and Telangana.

2.2 Compulsory Registration Irrespective of Turnover [Section 24]

Section 24 overrides Section 22, mandating compulsory registration from the very first rupee of commercial transaction for specific categories of suppliers:

2.3 Digital Registration Workflow on the GST Common Portal

Registration is executed paperlessly on gst.gov.in via statutory forms governed by Rules 8 to 26 of the CGST Rules, 2017:

1. Filing Part A of Form GST REG-01: The applicant submits their 10-digit PAN, legal business name, mobile number, and email address. The portal verifies the PAN with the CBDT database and validates contact details via separate OTPs. Successful validation generates a 15-digit Temporary Reference Number (TRN).
2. Filing Part B of Form GST REG-01: Using the TRN, the applicant logs in within 15 days to fill comprehensive business details: Trade Name, Constitution of Business, Principal Place of Business (with ownership proof/rent agreement and electricity bill), Additional Places of Business, details of Partners/Directors, bank account details, and top 5 HSN/SAC codes.
3. Aadhaar Authentication & ARN Generation: Promoters undergo biometric/OTP-based Aadhaar authentication. Upon successful submission with DSC/EVC, the system generates an Application Reference Number (ARN).
4. Proper Officer Verification: If the application and Aadhaar authentication are successful, approval is granted within 7 working days. If Aadhaar authentication fails or discrepancies arise, the officer issues a notice in Form GST REG-03 within 30 days. The applicant must reply in Form GST REG-04 within 7 working days.
5. Issuance of Certificate in Form GST REG-06: Upon approval, the system generates the Registration Certificate displaying the unique 15-digit Goods and Services Tax Identification Number (GSTIN).

2.4 Registration Amendments: Core vs. Non-Core Fields

Unit 3: Tariff Classification, HSN Codes & GST Rate Structure

3.1 Harmonized System of Nomenclature (HSN) & SAC Codes

To ensure standardized national and international classification of commodities, GST adopts the 8-digit Harmonized System of Nomenclature (HSN) developed by the World Customs Organization (WCO) for goods, alongside a 6-digit Service Accounting Code (SAC) system for commercial services.

• Chapters (Digits 1–2): Broad category of commodity (e.g., Chapter 09 for Coffee, Tea, Spices).
• Headings (Digits 3–4): Specific heading within chapter (e.g., 0902 for Tea).
• Sub-Headings (Digits 5–6): Specialized product sub-heading.
• Tariff Items (Digits 7–8): Granular national economic identification.

Mandatory HSN Reporting Rules on Invoices & Returns (Effective April 1, 2021)

3.2 The Five-Tier GST Rate Structure

Unit 4: Output Tax Liability & Return Filing: GSTR-1 & GSTR-3B

4.1 GSTR-1: Statement of Outward Supplies [Section 37]

GSTR-1 is the foundational monthly or quarterly return wherein a registered taxpayer reports invoice-level details of all outward supplies (sales) of goods and services. It dictates the Input Tax Credit (ITC) that will be auto-populated for the recipient:

• Table 4 (B2B Supplies): Taxable outward supplies made to registered persons (mandatory invoice-by-invoice reporting specifying recipient GSTIN, invoice number, date, value, and tax rate).
• Table 5 (B2C Large Supplies): Inter-state taxable supplies made to unregistered consumers where the invoice value exceeds ₹2.5 Lakhs (reported invoice-wise).
• Table 6 (Zero-Rated Supplies): Exports of goods/services (with or without payment of tax) and supplies made to SEZ developers/units.
• Table 7 (B2C Others): Intra-state supplies to unregistered persons and inter-state supplies up to ₹2.5 Lakhs (reported consolidated rate-wise).
• Table 8 (Nil-Rated & Exempt): Details of supplies exempt from GST or non-GST supplies (petroleum, alcohol).
• Table 9 & 10 (Amendments): Corrections to earlier period B2B, B2C Large, and export invoices, along with Credit Notes and Debit Notes issued.
• Table 12 (HSN-wise Summary): Comprehensive summary reporting HSN code, total quantity, total value, taxable value, and tax amounts.
• Table 13 (Document Issued Summary): Invoices, debit notes, credit notes, and delivery challans issued, cancelled, and net valid during the tax period.

4.2 GSTR-3B: Monthly Summary Return-cum-Payment [Section 39]

GSTR-3B is a self-assessed monthly summary return through which taxpayers declare summary totals of outward tax liability, reverse charge liability, claim Input Tax Credit, and execute actual payment of tax:

Unit 5: Input Tax Credit (ITC) & GSTR-2A vs. GSTR-2B Reconciliation

5.1 Statutory Conditions for Claiming Input Tax Credit [Section 16]

Input Tax Credit is the lifeblood of GST, eliminating the cascading effect ("tax-on-tax"). A registered person can claim ITC only upon satisfying all four fundamental conditions under Section 16(2):

1. Possession of Tax Invoice: The buyer must possess a valid tax invoice or debit note issued by a registered supplier containing all prescribed particulars.
2. Actual Receipt of Goods/Services: The registered person must have physically received the goods or services (or constructive receipt under bill-to-ship-to models).
3. Tax Deposited to Government: The tax charged by the supplier must have been actually paid to the Government, either in cash or through valid ITC utilization.
4. Return Furnished u/s 39: The recipient must have furnished their own return in Form GSTR-3B.
5. Mandatory 180-Day Payment Condition: The recipient must pay the supplier the value of the invoice along with tax within 180 days from the invoice date. If unpaid, the claimed ITC must be reversed along with interest, reclaimable upon subsequent payment.

5.2 Blocked Credits [Section 17(5) of CGST Act]

Notwithstanding Section 16, ITC is strictly inadmissible (blocked) for specific expenditures:

• Motor vehicles for transportation of persons having seating capacity ≤ 13 persons (except when used for commercial transportation, passenger transport, or driving school training).
• Food and beverages, outdoor catering, beauty treatment, health services, life/health insurance, except where used as an inward supply to provide the same category of service.
• Club memberships, health and fitness centre fees.
• Works contract services supplied for construction of an immovable property (other than plant and machinery) on own account.
• Goods lost, stolen, destroyed, written off, or disposed of by way of gift or free samples.

5.3 Comparative Matrix: Dynamic GSTR-2A vs. Static GSTR-2B

Unit 6: Online Tax Payment & The Three Electronic Ledgers

6.1 The Three Electronic Ledgers on the GST Portal [Section 49]

Every registered taxpayer has three distinct electronic ledgers maintained automatically on the common portal:

6.2 Online Tax Payment Workflow via Challan Form GST PMT-06

To deposit money into the Electronic Cash Ledger, the taxpayer generates Challan PMT-06:

• Major Heads: IGST, CGST, SGST, Cess.
• Minor Heads: Tax, Interest, Penalty, Fees, Others. (Funds deposited under one minor head cannot be offset against another minor head without filing transfer Form GST PMT-09).
• Validity: Challan PMT-06 is valid for 15 days from generation.
• Payment Rails: Net Banking, Debit/Credit Card, UPI, Over-the-Counter (cash/cheque up to ₹10,000 per challan per tax period), and NEFT/RTGS (generating CPIN).

6.3 Mandatory Statutory Hierarchy for ITC Utilization [Section 49A, 49B & Rule 88A]

To optimize tax distribution among Centre and States, the law prescribes a strict, non-negotiable order of setting off Input Tax Credit against Output Tax liabilities:

Practical Case Simulation: Multi-Head ITC Set-off Optimization under Rule 88A

Output Tax Liabilities: IGST = ₹50,000 | CGST = ₹30,000 | SGST = ₹30,000

Unit 7: Comprehensive Synthesis: The GST Return Lifecycle