Hello Aspirant,
If you are seeking admission in B.Tech course offered by NIT Kurukshetra then you have to get it through JOSAA counselling and the reservation certificate of EWS category should be of similar format as available on the official website of JOSAA which you can access through the link given below :-
https://josaa.nic.in/webinfo/File/GetFile?FileId=10&LangId=P
So whether you have Haryana sate EWS certificate or central EWS certificate it should be of similar format as available on the official website of JOSAA.
The same certificate you should upload it during JEE-Main application and If you don't have your reserved category certificate for EWS category right now then you can submit the undertaking which declares that you will submit the original and valid caste certificate later on at the time of admission. You can download the undertaking from the official portal of NTA, for which link is also given below :-
https://jeemain.nta.nic.in/webinfo2021/File/GetFile?FileId=5&LangId=P
When you visit on the above link you will find a PDF and on page no.9 there is undertaking format which you have to download and after filling it you have to upload it on the place of category certificate in the JEE-Main 2021 Application form.
I hope this information helps you.
Good Luck!!
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