PRAYAGRAJ, Sept. 1 -- The Central Board of Secondary Education (CBSE) has asked all the principals of its affiliated schools (around 25,902) to ensure completion of National Initiatives for School Heads' and Teachers' Holistic Advancement (NISHTHA) courses by secondary level (Class 9-12) teachers as per the timetable shared by National Council of Educational Research and Training (NCERT), according to CBSE officials....