Central Board Of Secondary Education [CBSE] — leaving subject in class xii while registering

Address:

Kamrup Metropolitan, Assam, 781019

It was known that once the students have chosen the subjects in class xi after registration they cannot leave the subject. But it is seen seen that in class xii duringregistration many students leave subject as the option is there. Being a pgt computer science i have always been humiliated on leaving comp. Sc. If the student can leave subjects just before xii resitration what is the use of giving circular declaring that students cannot cannot leave subject after class xi resitration. Please give a transparent circular regarding this. Otherwise the omputer science teachers always have to suffer mentally.