With the rapid growth of urbanization and increasing population, effective waste management has become a significant challenge in terms of public health and sanitation for municipalities worldwide. To address the issue, Internet of Things (IoT) based smart waste management systems can be a solution to optimize waste collection processes with reduced operational costs, for promoting environmental sustainability. The proposed work presents the development of a smart dustbin using an IoT-based platform, i.e., NodeMCU and ThingSpeak cloud platform. The proposed system integrates ultrasonic sensors with NodeMCU to monitor the level of waste in real time. The ultrasonic sensor measures the level of waste inside the dustbin, and the NodeMCU board sends this data to the ThingSpeak cloud platform via Wi-Fi. The collected data is analyzed to determine the fill level of the dustbin. When the dustbin reaches a pre-defined threshold level, an alert is generated to notify the waste management system. The system's scalability and flexibility promote easier deployment in various urban and industrial environments, offering a promising approach to tackle the challenges of modern waste management. Experimental results prove the implementation efficiency of the method.