A few of my friends graduated from Thapar University and here are some facts for you which might give you better information.
You can migrate to Thapar University in December as it conducts an entrance test for the remaining seats of the university. The regular first-year students may also apply for getting their branches upgraded if the seats are vacant.
The test is based on the course of 11th and 12th grade and some of the first semester subjects.
Do check with Thapar Institute of Engineering and Technology University to stay updated. Also, keep a watch on the official website of Thapar University to apply for the December test.