HSN code in gstr 1

If the turnover exceeds 1.5 crore then hsn summary is compulsory

Act is silent as mentioned in provision that, if turnover doesn't exceed 1.5 crore. Supplier doesn't need to mention HSN in Invoice, but silent for GSTR-1 reporting. From this we are presuming the same for GSTR-1.

notification 12/2017 CT , Dr 28/6/17

provides that a registered person having annual turnover in the preceding financial year less than Rs.1 .5 Crore is not required to mention the digits of HSN codes in a tax invoice issued by him. However, in GSTR 1 & 2 he must give the details of stock sold HSN code wise.
So person having turnover up to Rs 1.5 crore may skip HSN codes but they have to provide quantitative details and descripttion of all items sold.