For national level entrance exams like NEET ,JEE and many more the rules followed by centres are very strict . So ,you to must follow the guidelines as it is given instead of being late you must atleast report an hour early cause they are some procedures they do before taking you in your class .

You need to report to the exam hall atleast an hour before the exam for checking because therea re additional measures being take like:

• Contact less frisking will be ensured.
• Time slots will be staggered for Reporting to the exam
• Contact less verification of documents
• Candidates will have to carry a self declaration regarding their Corona free health status
• Candidates with more than required body temperature will be allowed to take the exam in isolated rooms

So if you do not report on time, you will not be allowed to enter the examination hall.