Reclaimed water · 15L · Converting wastewater into water that can be reused for other purposes
Low-carbon economy · 7L · Economy based on energy sources with low levels of greenhouse gas emissions
Wave power · 8L · Transport of energy by wind waves, and the capture of that energy to do useful work
Electric car · 8L · Car propelled by an electric motor using energy stored in rechargeable batteries
Biofuel · 19L · fuel that is produced through contemporary biological processes, as opposed to fossil fuel that was produced by prehistoric bio-geological processes
Environmentally friendly · 4L · goods, services, laws, and rules that either do not harm the environment or do very little harm to it
Organic farming · 8L · Method of agriculture meant to be environmentally friendly