Mexico is the second country in the world to have to have instituted legally binding targets on GHG emission reductions. The law mandates a reduction in CO2 emissions by 30% below business-as-usual levels by 2020, and by 50% below 2000 levels by 2050 (note that this is a relative target – the UK’s target is an absolute one)
It also stipulates that 35% of the country's electricity should come from renewable sources by 2024, and requires mandatory emissions reporting by the country's largest polluters. In addition, the act establishes a commission to oversee implementation, and encourages the development of a carbon-trading scheme. Mexico ranks 11th in the world for both the size of its economy and its level of carbon emissions.
For more information see here.