Under the Income Tax Act,1961 all entities (Companies, partnership firms, Sole proprietorships) should go through a Tax Audit if their turnover exceeds INR 1 crore. For practicing professionals the gross receipts limit is INR 50 lakhs.
The tax audit is to be conducted by a Chartered Accountant.
GST Audit Limit is prescribed under the CGST Act,2017 which is to be read with notifications issued by CBIC on time to time. The audit report has to be filed with the concerned tax authorities within due dates prescribed.