Dear student,
Most probably you have no option except showing then the caste certificate in the format they have asked.
But please tell me one thing in comment section or in new question that what is their format type that you cannot make it in Bihar? If this is the case then lot of SC candidates will have to suffer with this problem and i am not sure if IIT system will like this,
or are they asking the signature of higher authority than currently you have on your caste certificate? If this is the case then you must have to visit that authority carrying your caste certificate that you presently have, explain him/her the situation and then he/she will definitely sign on it.
If everything fail and you are not able to furnish the required certificate then you can carry the certificate you presently have and explain them during counselling that why you were not able to create that format, maybe they will understand it. But I strongly recommend you to try to make the certificate in the format they are asking for not experiencing panic during counselling time.
I hope this information helps you.
You can check more undates about JEE advanced 2021 by going through the link below.
https://www.google.com/amp/s/engineering.careers360.com/articles/jee-advanced-application-form/amp
All the very best!!
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