Hi,
Find it yourself if there is any 50% rule.
1. Rules as applicable to Indian students (for all categories)
http://www.vfsglobal.ca/canada/india/study_permits.html
2. Checklist and questionnaire (India)
http://www.canadavisa.com/canada-immigration-discussion-board/index.php?action=post;quote=3888813;topic=256016.0;num_replies=13;sesc=cbc2e4a30535b90b31a49cf16f2c7d54