Turnover Exceeds 20/10 Lakh
If the aggregate turnover is more than 20 lakh (Rs. 10 lakh for North Eastern States) then GST registration is necessary and must be obtained within 30 days of reaching to that level.
Inter-state Sales or Service
If you are engaged in the supply of goods or services to customers in another state then regardless of turnover, you need to obtain the registration before commencing any interstate trade.