Think of Section 22 as the normal registration rule — if your turnover crosses ₹20 lakhs (₹10 lakhs in special category states), you register. Section 24 is the override button. It says: regardless of your turnover, if you fall into any of these 12 categories, you must register. Even if you sold just ₹1 worth of goods, registration is mandatory. No threshold applies.
Who are these 12 people? Let's group them logically for the exam. Inter-state suppliers — if Rajesh & Co. in Mumbai sells to a customer in Delhi, that's an inter-State taxable supply, and Rajesh must register even if his turnover is ₹5 lakhs. Casual Taxable Persons (CTPs) are those who occasionally do business in a state where they have no fixed place of business — like a Delhi vendor setting up a stall at a Bengaluru trade fair. Non-Resident Taxable Persons (NRTPs) are the foreign equivalent of CTPs. Reverse Charge Mechanism (RCM) payees — if you are required to pay GST directly to the government on behalf of the supplier (e.g., buying from an unregistered dealer in notified categories), you must register. TDS deductors under Section 51 (government departments, PSUs, etc.) must register even if they are separately registered. Agents making taxable supplies on behalf of other persons must register. Input Service Distributors (ISDs) — a head office that receives invoices for services and distributes the credit to its branches — must register. E-commerce operators required to collect Tax at Source (TCS) under Section 52 (like Amazon, Flipkart) must register. Suppliers through e-commerce platforms (if the e-commerce operator is required to collect TCS) must also register — no turnover exemption for them. Finally, OIDAR service providers — foreign companies supplying online information, database, or retrieval services (like Netflix, Spotify, cloud software) to non-registered Indian consumers must register in India.
This section is asked frequently as a 4-mark or 5-mark question in both MCQ and descriptive formats. The examiner loves asking "Is registration compulsory for X? Give reason" — so know all 12 categories cold.
Example 1: The Small Inter-State Seller
Ms. Iyer runs a handloom business in Tamil Nadu. Her annual turnover is ₹8,00,000 (₹8 lakhs). She receives an order from a buyer in Karnataka.
Working:
- Normal threshold (special category state TN): ₹10,00,000
- Ms. Iyer's turnover: ₹8,00,000 — below threshold under Section 22
- BUT: She is making an inter-State taxable supply → Section 24(i) applies
- Section 24 overrides Section 22 completely
Answer: Ms. Iyer is compulsorily required to register under GST before making this supply. Turnover is irrelevant.
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Example 2: The Trade Fair Vendor (Casual Taxable Person)
Mr. Sharma is a Delhi-based garment manufacturer (registered in Delhi). He wants to set up a stall at a 15-day fashion expo in Jaipur, Rajasthan. Expected sales at the expo: ₹3,00,000.
Working:
- Mr. Sharma has no fixed place of business in Rajasthan
- He is a Casual Taxable Person for Rajasthan → Section 24(ii) applies
- Turnover of ₹3,00,000 is irrelevant — threshold does NOT apply
- He must obtain a temporary GST registration in Rajasthan at least 5 days before the event
- He must make an advance deposit of estimated tax liability
Answer: Mr. Sharma must compulsorily register in Rajasthan as a Casual Taxable Person. His Delhi registration does not cover Rajasthan supplies.
📖 Bare Act text — Section 24, CGST Act 2017
(click to expand)
Notwithstanding anything contained in sub-section (1) of section 22, the following categories of persons shall be required to be registered under this Act,––
(i) persons making any inter-State taxable supply;
(ii) casual taxable persons making taxable supply;
(iii) persons who are required to pay tax under reverse charge;
(iv) person who are required to pay tax under sub-section (5) of section 9;
(v) non-resident taxable persons making taxable supply;
(vi) persons who are required to deduct tax under section 51, whether or not separately registered under this Act;
(vii) persons who make taxable supply of goods or services or both on behalf of other taxable persons whether as an agent or otherwise;
(viii) Input Service Distributor, whether or not separately registered under this Act;
(ix) persons who supply goods or services or both, other than supplies specified under sub-section (5) of section 9, through such electronic commerce operator who is required to collect tax at source under section 52;
(x) every electronic commerce operator [who is required to collect tax at source under section 52;]
(xi) every person supplying online information and database access or retrieval services from a place outside India to a person in India, other than a registered person; and
(xii) such other person or class of persons as may be notified by the Government on the recommendations of the Council.