Hello Raj more, 

CLAT is a national level exam for LAW to National Law University, it does not need any domicile certificate to apply for CLAT across India. However, during the time of admission some NLUs have a few seats reserved for students of that particular state. Having a domicile certificate would be helpful at that stage.

Example - Domicile is needed only when you are planning to give any state level exam (eg MH CET) other than your own state.Under domicile, you will be considered citizen of same state (Like Maharashtra even if you are from other state) and you will get preference while applying...

All the best and Thank you.

Hello!!!

 Domicile and birth certificate are two different things. Domicile proves that you have a residence in a particular place but birth certificate just proves that you were born at some particular place. But it doesn't at all prove that you have a residence there. So you do need a domicile certificate to show that you a resident of a particular state.