Hi,

The National Institute of Open Schooling, formerly National Open School, is the board of education under the Union Government of India. No, you cannot apply for nois science with only 4 subjects. They have clearly stated that for obtaining a pass certificate you are required to pass in minimum 5 subjects which should include one or two languages from Group A and three or four subjects from the other group. I hope this clears you doubts and if you still have any, I'm here to help you.

I hope this helps,

All the best.