An innovative approach to enhance supply chain process performance is the vendor-buyer integrated inventory model. Our civilization is currently dealing with a lot of environmental contamination. Global destruction of the environment has prompted us to move away out conventional to eco-friendly items. Therefore, a manufacturing firm's carbon pollution can be controlled by investing in emission reduction processes. By assuming demand that is depending on a selling price and greenness level, this article examines the products that are produced by the vendor and delivered to the consumer with the influence of collaborative investment in emission reduction process. This model considers a production fault, resulting in quality inspection errors at the buyer's end and learning in the production process at the vendor's end. The model is validated with a numerical example.