This paper focuses on upstream supply chain management
activities, which are usually responsible for diffusing environmental
sustainability practices across the supply base.
They are also considered the ways by which suppliers are
engaged to reduce waste and preserve the natural resources
[5] and to reach higher levels of sustainability [6]. In addition,
environmental sustainability practices across upstream SCM
are linked to input and output-oriented environmental factors
[7]. For example, input-oriented factors include energy (consumption
and source – renewable or not), natural resource and
materials, water (quality and demand) and output-oriented
factors are related to waste and pollution.