Diwali gift to employee

Hi rani,
First we will check that gift given to employee by an employer is within ambit of scope of supply or not. there are two cases
1. if gift given by employer to employee exceeds rs 50000 in a FY - then it will be treated as supply of goods as per schedule I of CGST ACT 2017 as it comes under scope of supply mentioned under Sec 7(2) of Act, hence chargable to gst of fair market value i.e. in invoce in your output tax liabilty even if gift is given without consideration . And you will be allowed to take credit. this will nullify the tax payment and credit availed.
2. When gift given are less than 50000 in FY - it is neither a supply of goods nor service. hence as per defination of exempt supply hence credit exclusively used in exempt or non gst or no gst supply cannot be availed.

What mean by HGST...?

Genrally HGST is short from of S(statename)GST - So it may be hariyana GST or Himachal Pradesh GST ... Please see the advance rulling order .. they term like state wise - rajasthan state gst read as RGST .
I think it is ok

ITC not available for the gift purchase.

ITC not available on goods disposed off by way of Gift. Refer the Provision of Section 17(5) clause (h) of the CGST Act 2017.

I also agree with Mukesh Sharma Sir's explanation.