The intention of sustainable design is to "eliminate negative environmental impact completely through skillful, sensitive design". Manifestations of sustainable design require renewable resources and innovation to impact the environment minimally, and connect people with the natural environment.
Environmental sustainability occurs when natural resources are preserved. Monocropping, pesticides, and fertilizers all deplete good soil. When that soil becomes sterile, it can no longer produce food. That's one example of environmental sustainability.
The term sustainability is broadly used to indicate programs, initiatives and actions aimed at the preservation of a particular resource. However, it actually refers to four distinct areas: human, social, economic and environmental – known as the four pillars of sustainability.
Sustainable product design is about you doing the right thing for the planet. It includes picking the materials that suit your design, that support your carbon footprint target, that are not harmful during use, and that can be used again.