Hello,

Allotment of seats is purely based on merit of candidates in the qualifying exam.Along with overall rank list ,community rank list is also prepared.They have reservation criteria for some communities and it means that much percentage is reserved for that category students only and then the overall rank .Final seat allotment is made on basis of overall rank ,community rank and reservation applicable.For BC it is 26.50% ,BCM 3.50%,SC 15% ,ST 1%,SCA 3%.you may check the link below for more details.I hope it helped.

https://engineering.careers360.com/articles/tnea-seat-reservation