Green chemistry is an approach to chemical research and production that aims to prevent pollution at its source rather than treating it after it occurs. It is guided by a set of principles that encourage safer substances, efficient processes, and the reduction of waste and energy use throughout a product’s life cycle.

A central idea is designing chemical reactions that use fewer hazardous reagents and produce little or no toxic by‑products. Catalysts are preferred over stoichiometric reagents because they can drive reactions repeatedly without being consumed, improving both efficiency and safety. Solvent choice is another key area, with emphasis on water or other benign solvents instead of volatile organic compounds that contribute to air pollution and health risks.

Atom economy and energy efficiency are crucial metrics. Reactions are evaluated on how many of the atoms in the starting materials end up in the final product, and whether the process can proceed at ambient temperature and pressure to reduce energy demand. Where possible, renewable feedstocks such as biomass replace petrochemical sources, and processes are designed to be easily scaled while maintaining low environmental impact.

Green chemistry also considers product design. Chemicals and materials are tailored to be effective in use but to degrade into harmless substances at the end of their life, reducing long term persistence in the environment. This approach connects scientific innovation with regulatory, economic, and societal pressures, encouraging industries to adopt cleaner technologies, reduce costs associated with waste and compliance, and support a more sustainable industrial system.