Obama might never pass an environmental law during his term as President as he is relying heavily on the Clean Air Act of 1970. However, he will leave office with the most aggressive environmental legacy than any other President has managed to achieve during their terms in office.
Considering to be the most powerful environmental law on the planet, and also because Congress has blocked his attempts to pass any law on the environment, he is using this law to pass first-of-its-kind regulations to limit air pollution on a variety of issues such as soot and smog, mercury and carbon-dioxide
Despite this, the environment legacy that Obama wants to leave behind could be overturned by the Supreme Court. Until now, they have upheld these regulations in three separate cases. More challenges are up ahead with the most recent of them dealing with mercury emissions from coal-fueled power plants.
The Clean Air Act, in this instance, is coming under attack from the industry as well, as it gives the Environmental Protection Agency the flexibility to interpret the law.
In other words, this could lead to the United States’ first national policy on global warming which could shut down existed coal-based power plants and prevent the construction of new ones too
And there despite the Republicans calling this the war on coal, even if smog is related to asthma, premature death and heart disease, more regulations are on the way later this year. The first of which will include regulation of methane emissions at natural gas facilities.