Mario Molina was a Mexican chemist who made a groundbreaking contribution to science by discovering the threat of chlorofluorocarbons (CFCs) to the ozone layer.

Here's a breakdown of his key achievements:

* 1974: Discovery of the Ozone Hole: Along with F. Sherwood Rowland, Molina published a paper showing how CFCs, then widely used in refrigerants and aerosol sprays, could deplete the ozone layer in the stratosphere. This layer protects life on Earth from harmful ultraviolet radiation from the sun.

* 1995: Nobel Prize in Chemistry: Molina and Rowland were awarded the Nobel Prize in Chemistry for their work on the ozone layer, recognizing the critical importance of their research in raising awareness about the environmental threat posed by CFCs.

* Advocacy and Policy Impact: Their discovery led to international agreements, including the Montreal Protocol, which phased out the production and use of ozone-depleting substances. This global effort has significantly reduced the depletion of the ozone layer and is considered a major environmental success story.

Molina's work not only advanced our understanding of atmospheric chemistry but also had a direct impact on policy and environmental protection. He continued to be a leading voice in advocating for science-based solutions to environmental challenges throughout his life.