Persons requiring registration without threshold limit of Rs. 20/10 lakhs :
The following categories of persons shall be required to be registered under this Act, even if their aggregate turnover is below specified limit.
(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) persons who are required to pay tax under section 9(5) [electronic commerce operators]
(v) non-resident taxable persons making taxable supply.
(vi) persons who are required to deduct tax under section 51 (TDS), whether or not separately registered under the Act [Thus, separate registration is required for TDS purposes]
(vii) persons who supply 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 the Act [Thus, separate registration is required for ISD purposes]
(ix) persons who supply goods or services or both, other than supplies specified under section 9(5), through such electronic commerce operator who is required to collect tax under section 52 [Under section 9(5) of CGST Act, Government can notify e-commerce operators who will be liable to pay entire GST]
(x) every electronic commerce operator.
(xi) every person supplying online information and data base access or retrieval services (OIDAR) from a place outside India to a person in India, other than a registered taxable person [Thus, if a person is already registered under GST, separate registration is not required] and
(xii) such other person or class of persons as may be notified by the Central Government or a State Government on the recommendations of the GST Council.