Green chemistry aims to reduce or eliminate the use of hazardous substances in chemical products and processes. It promotes the use of renewable feedstocks, safer solvents and auxiliaries, catalysts over reagents, and design of chemicals that degrade harmlessly after use. The 12 principles of green chemistry provide a framework for designing chemical syntheses and products that are less hazardous to human health and the environment. Green chemistry can help address issues of energy use, global climate change, resource depletion, food supply challenges, and toxic pollution.