The Emissions Trading Systems (SCE in Spanish), together with carbon taxes, are a strategy to combat climate change that establishes a price for polluting emissions. Up to 2018, there were 47 initiatives of this type in the world and, derived from these initiatives, in 2017 the governments had revenues of $ 33 billion dollars. In this regard, the Mexican government raises the SCE as a strategy to comply with the commitments established in the Paris Agreement. In July 2018, the General Law of Climate Change was updated to establish the creation of a compulsory SCE that was previously described as voluntary.