A Green Inventory Model for New and Revamped Decaying Products with Partially Backlogged and Stock Dependent Demand

In response to increasing awareness of the need to maintain a healthy environment, supply chain sustainability has become a major topic of discussion in recent years. It focuses on green practices in order to minimize environmental degradation and increase its economic and operational performance. Its primary goal is to integrate environmental issues such as carbon emissions. For a single item that degrades naturally, this study suggests a three-tier green supply model of inventory, including demand based on stock, shortages (permitted at the retailer’s end), and carbon emissions. Integrated cost minimization and critical time optimization are achieved with this work. New items are delivered by the producer and moved to the retailer. Remanufacturing of a product is a green practice. Defective items are returned once again to the producer by retailers for remanufacturing. For the purpose of analyzing how inventory parameters affect decision-making, a sensitivity analysis is presented. The model’s validity is confirmed by using numerical illustrations, and convexity is shown graphically.