‘Explanation.––For the purposes of this sub-section, the expression “self-assessed tax” shall include the tax payable in respect of details of outward supplies furnished under section 37, but not included in the return furnished under section 39.
Thus, any tax reflected in GSTR-1, but not shown in GSTR 3B shall be considered as self-assessed tax and shall be liable to be recovered straightaway under section 79.