GST regulations are applicable if your annual turnover is
Rs. 40 Lakh or above in case of Goods.In case of North Eastern states (Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, and Tripura) and hilly regions i.e. Himachal Pradesh, Uttarakhand,Jammu & Kashmir and Sikkim, the threshold limit is Rs. 20 lakh.
Rs. 20 lakh or above. In case of North Eastern states (Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, and Tripura) and hilly regions i.e. Himachal Pradesh, Uttarakhand,Jammu & Kashmir and Sikkim, the threshold limit is Rs. 10 lakh.
The registration is mandatory on crossing the limit of Rs.19,00,000 in previous financial year( for special category states it is Rs. 9,00,000).
Note: If you are selling your goods through online platforms like amazon, Flipkart etc, GST registration is mandatory.