Waste Not, Want Not
This is a primer for the Ciruclar Economy. This would mean that nothing enters a landfill, nothing is waste, and everything is continuously usable. All materials are kept in circulation via maintenance, remanufacturing, composting, and creative reuse.
This tackles a ton of issues our world is currently facing from pollution to biodiversity loss by decoupling from the linear economy. The Linear Economy takes materials, uses them for a short while, and throw them out. A Circular Economy would make 'waste' obsolete.