Is the HSN CODE Mandatory

As per Notification 78/2020 CT :

Aggregate Turnover more then 5 Crore:
6 Digit HSN code shall be mentioned mandatory on Tax Invoice.

Aggregate Turnover less then 5 crore :
4Digit HSN code shall be mentioned for B2B supply in Tax invoice.

Hence from above it's being very clear that Reporting HSN is in Tax Invoice & the particular in tax invoice need to be mentioned as accordingly in GSTR 1.

So in my view the Registered person whose turnover is below 5 crore is not required to provide HSN for B2C supply in Table 13 of GSTR 1

Agree with Pankaj Sir's view...
Quoting of HSN Code in Tax Invoice in the case of B2C Supply by the taxpayer having aggregate turnover upto Rs. 5 crores is "OPTIONAL." So there is no need to mention HSN Summary in FORM GSTR-1 if you have only B2C Supply.

From the descripttion of Pankaj Rawat sir and Shivam sir I understand that the taxpayers who handles only less ₹ 5 crore outward supply and only B2C invoices does not need to mention the HSN Cide in the GSTR 1.

No HSN code is not required