Hello Aspirant,

It would be good if you reach their by 11:40 am at examination center because there are some formalities from which you have to go through and specially this year some guidelines have been changed in the wake of COVID-19 and no crowd should be gathered their. But if anyhow you cannot reach their by 11:40 am then you should reach at examination center must before the Gate closing time that is 1:00 PM after this entry will not be allowed because exam timing is from 2:00 pm to 5:00 pm and you have to give your attendance also prior to the exam.

To read complete guidelines issued by NTA refer to the link given below :-

https://www.google.com/amp/s/medicine.careers360.com/articles/neet-exam-day-guideline/amp

I hope this information helps you.

Good Luck!!