<p>Patna, one of the growing cities in India, also has concerns about solid waste management due to its expansion with increasing population, making it critical to the sustainability of the city. In the above context, the study aims to identify the suitability of landfill sites for managing solid waste in Indian cities, such as Patna, which is developing as a planned and smart city in the country. Using 10 key criteria ranging from environmental to socio-economic and human settlement, the study has employed the AHP and fuzzy AHP models, multi-criteria-decision-making methods for solving decisions involving multiple criteria, to assess the suitability of landfill sites. Unlike the previous studies, which applied these methods independently, the present study integrates both models and systematically integrates them to generate a more reliable and robust output suitable for a map. The study indicates that less than one-tenth of the study area is suitable for landfill sitings, while the majority of the area is not favourable for landfill sitings. The outcomes of both models suggest a minimal proportion of area, but sufficient to be favourable for landfill sites. The very highly suitable sites are mainly concentrated in the fringe areas of the city, particularly the southern, north-western, and south-eastern parts of the study area. The middle and northern parts of the city are considered less suitable due to the dense built-up area in the middle part of the city and river in the North. The reliability of output maps of the models was validated visually through Google Earth. Undeniably, the city needs sustainable landfill sites in suitable locations through proper planning and management, and the study findings will certainly contribute to designing and implementing a sustainable city.</p>