Sustainability is a critical focus in contemporary research, and the integration of mathematics with advanced technology can significantly reduce our carbon footprint. Mathematical tools are essential for simulating and analysing environmental systems, which helps us understand the impact of human activities and evaluate the effectiveness of potential solutions. Additionally, these tools are vital for processing the vast amounts of data generated by IoT devices. The article explores the synergy between mathematics and IoT, highlighting how this combination can contribute to the development of more sustainable cities. Through a content analysis of relevant publications, the article proposes innovative processes and a variety of mathematical tools that, when leveraged with technology, can enhance urban sustainability. Artificial intelligence (AI) also plays a crucial role in this context. AI algorithms can learn from historical data to predict energy consumption patterns, resource usage, and potential environmental disruptions. They can analyse waste collection data to optimize routes, forecast waste generation, and identify opportunities for recycling and reuse. IoT networks facilitate data collection, revealing trends, pinpointing areas for improvement, and measuring the impact of sustainability initiatives. However, several challenges arise from this integration. The large volume of data necessitates efficient computational tools for processing. Data variability complicates analysis, while security and privacy issues pose additional concerns. Moreover, there is a shortage of specialists capable of analysing and applying IoT data effectively.