This research study investigates the cognitive levels of the questions used for assessment and evaluation purpose in three national school board secondary school leaving examinations in Science and Mathematics, conducted in Indian schools from 2011 to 2020. The research used Bloom's Taxonomy to identify the cognitive levels of 3071 exam questions. The study addresses the gap in the current literature on the non-availability of a comparative study of national school board assessment practices in India. The study provides a comparative analysis of three English medium Indian school boards (ICSE, CBSE, and NIOS) by analyzing what areas/topics the board exams test and which ones they ignore. Based on this analysis, certain trends were analysed which are present in boards/subjects in the 10th standard national level exams in India. This study will help school education stakeholders to get an insight into the cognitive level trend/patterns of assessment questions.