As far as IT Act is concerned basic company details are public information. Similarly, details associated with a GST number are public information since they are basic data.
Whether GST number is private data?
As per GST rules, GST number has to be mentioned on every document, website, company communication letters, on address board etc. This implies that GST number is not private information and one can access all details associated with GST numbers on many websites.
GST numbers and its associated details are public information.