WHAT MAKES THE ~20-LAKH THRESHOLD IRRELEVANT

One would be required to register for GST irrespective of whether one meets the threshold or not:

Persons making any inter-state taxable supply

Casual taxable persons making taxable supply

Persons required to pay tax under reverse charge

Non-resident taxable persons making taxable supply

A person who makes taxable supply of goods or services on behalf of other taxable persons

Input service distributor, whether or not separately registered under this Act

Persons who supply goods or services through an e-commerce operator

Every e-commerce operator

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