The JEE Mains exam is the entry level exam for all candidates across the India to get admissions in the government engineering colleges. It is held every year in multiple sessions. However the JEE Exam is not held for different states differently. The JEE exam is held on multiple days in multiple sessions but the question paper of a session remains the same. It only varies as per the sessions. So, the exam is held across the India in multiple sessions but the question paper of one session does not vary across the state but vary as per the multiple sessions. You can further can get information from the official NTA website about the exam. Hope this resolves your query.