The pandemic, COVID 19, has affected global economy severely which caused an outbreak of crisis in all sectors of business. Firms are struggling to keep up with the normal functions in different stages of supply chain which brought sustainability under a big risk. Concerned by the COVID-19 outbreak, the main aim of this paper is to determine the threatening barriers to supply chain sustainability in the pharmaceutical industry of the South Asian region. This industry is one of the most pivotal and developing sectors in the south Asian region with respect to other industries in this region. Although economic growth is noticeable in this sector, many questions are arising about its sustainability and resilience in a true sense amidst the global pandemic. To establish the sustainability of this sector under a pandemic scenario, the major barriers in terms of social, economic, and environmental perspectives have been identified and analyzed in this research. Twenty crucial constraints have been identified and classified in five categories through an extensive study of literature and the opinion of an industry experts. This paper uses, Interpretive Structural Modelling (ISM) approach to develop the hierarchical structure and connection between these obstacles. ISM presents the interdependency of the driving and driven power of these barriers. Another modernistic approach, the Matrix of Cross-Impact Multiplications Applied to Classification (MICMAC), has been used to recognize the barriers as driving factors, dependent variables, and link variables using. The modeling of this study provides companies insight into obstacles and the efficient and effective management of their resources while making their supply chains sustainable. The study closes by discussing findings and future areas of the research.