is it true that we must join the alloted college in 2nd allotment and we must return from the college we are already alloted by state allotment in the 1st allotment?

Hi.

I am going to answer this assuming you are referring to CSAB Counselling.

So, YES it is mandatory to join the college allotted to you in the 2nd round of counselling. Because, the college has been allotted to you by your own choice of seat upgradation, depending on the fact that you chose the option to FLOAT i.e. to get a college which was higher in preference in your locked choices.

Please NOTE: Failing to report to the college, after submitting documents for verification is CSAB will result in seat forfeit and no refund will be given. You can check the official CSAB Rules at this page:

https://csab.nic.in/WebInfo/File/GetFile?FileId=18&LangId=P

Best of Luck