Turnover under 20 lakh still GST registration required in the following conditions :
1. If an entrepreneur or service provider supplies goods or services from one state to another.
2. Casual taxable person like businessman who does not trade from a permanent place or sometimes does business from different places.
3. Traders who purchase goods from un-registered dealers and have the responsibility of Tax payament under the reverse charge system.
4. E-commerce operator i.e. a supplier who is doing business online through a website like amazon, flipkart, snapdeal and so more... they are not selling goods still they providing a platform and collect fees for that.
5. Non-resident person / firm / company when they supply taxable goods or services.
6. All government agencies and departments, who have the obligation to deduct tds on purchase of more than 2.50 lakh rupees.
7. Agent who provides goods or services on beahlf of registered dealer.
8. Input service distributor, such as Regional / Zonal Office of Banks who take all the input and distribute amongs branches on the prorata basis.
9. Operators who offer services through e-commerce Such as hotels providing service through make mytrip.com or persons registered on amazon, flipkartor snapdeal for selling goods.
10. People who live outside of India and doing business or giving services in india.
11. in the same manner if an indian person doing online business and giving services or sold goods to another state or giving services to another country then under reverse charge he is liable for tax so he is liable to register.
All the above traders, service providers and government departments are required to register under GST act, even though their annual turnover is less than Rs.20 lakhs.