Hey Ritika,

Hope you are doing well!

Well dear,you don't need to study a particular subject for CLAT,as CLAT asks questions in terms of English,GK,Legal Aptitude,Logical Reasoning and Mathematics.

And,Yes you can prepare for it after your Board exams but the thing is you have to work deeply on it keeping aside all the distractions.

Also,for more information you may go on the link below:

https://law.careers360.com/articles/how-prepare-for-clat-without-coaching

Hope This was helpful!

All the Best!

Keep Smiling :)