The current study compared the achievements of higher secondary level students before and during the COVID 19 pandemic in five subjects-English, Biology, Physics, Chemistry, and Mathematics. This study was conducted on higher secondary level students from Bodoland Territorial Region (BTR), Assam, India. Dichotomous variables like rural and urban, tribal and non-tribal are considered for sample collection. A stratified random sampling technique is used for data collection. When five subjects are considered as a unit, the Mahalanobis Distance (MD) is used to measure the difference in dynamical character of achievements. There is a significant difference in the achievement of students between pre-COVID 19 and during COVID 19 pandemic. [ABSTRACT FROM AUTHOR]