The study analyzes the underlying reasons and ensuing consequences of Chattogram city's development in Bangladesh, which diverges from the principles of sustainable development. This research employs mixed-method approaches incorporating primary data to achieve its objectives. The primary data is based on a survey, interview, the author's experience, and participatory observation in Chattogram city. Furthermore, it critically examines the existing literature to develop a theoretical understanding of Chattogram city's sustainable development and its sustainable environmental nexus.The results indicate that the expansion of Chattogram city's urbanization and industrialization is proceeding at a rapid pace; however, it is occurring in an uncoordinated and unsustainable manner that neglects environmental protection. Consequently, the city's development falls short of aligning with environmental sustainability and is liable to induce negative ramifications on the environment, human health, biodiversity, and climate. The study pinpoints several factors contributing to environmental degradation, including environmental mismanagement, non-existence of a master plan, environmental illiteracy, absence of carbon emission objectives, and haphazard industrialization and urbanization. Importantly, the issue has been exacerbated due to the inadequate focus on sustainability in the developmental process. Therefore, the findings of this research indicate that a sustainable development perspective is required to comprehend and address the issue of environmental degradation in Chattogram city. In addition, the comprehensive sustainable development strategy and policy recommendations proposed in this study are likely to be efficacious in curbing environmental degradation in Chattogram and other developing cities.