Scheme of studies
CBSE's official document listing every subject, code and rule for Classes 11 and 12.
The scheme of studies is published each year on cbseacademic.nic.in. It lists subject codes, which combinations are not allowed, the number of subjects, and internal (school-assessed) subjects.
This site follows the scheme for the current session. If a rule here and your school's circular disagree, the school and the latest CBSE circular win.