Hello Ambrish,
You have not given any prior information regarding which exam you are talking about. I guess you are asking about neet.
Jeans are not allowed in the exam centre. Neet have strictly prohibited the jeans in their exam centres. Other queries can be cleared here.
https://www.google.com/amp/s/medicine.careers360.com/articles/neet-dress-code/amp
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile