Finding ways to assess and measure the impact of tourism and its associated development on sustainability is critical to developing long-term sustainability plans for regions such as the Indian Himalayas. Among the methods proposed is ecological footprint (EF) analysis or appropriated carrying capacity analysis. EF analysis estimates the area of productive land and water ecosystems required to produce the resources that a population consumes and to assimilate the wastes that the population produces in supporting itself. This study used EF analysis to quantify the sustainability of Manali, a rapidly growing tourist center in Kullu District, Himachal Pradesh, India. It considered the changes in the size of Manali's footprint since the advent of mass tourism in the early 1980s, the direct impact that tourists are having on the size of the footprint, and the challenges of applying this analysis in a developing world context. Data regarding land use, goods and services, and population were collected through local interviews and available data. The results indicate that between 1971 and 1995, the overall EF of Manali town grew from 2102 to 9665 ha, an increase of over 450%; the EF of Manali is now 25 times greater than its size. This indicates that Manali is increasingly relying on outside ecosystems for its sustenance. The article highlights areas of focus for future sustainability planning, including waste management, decreasing fossil fuel dependence, ecofriendly tourism, and creating greater environmental awareness, particularly among tourists.