Please answer a question about the following article about New York City:

The city government was a petitioner in the landmark Massachusetts v. Environmental Protection Agency Supreme Court case forcing the EPA to regulate greenhouse gases as pollutants. The city is also a leader in the construction of energy-efficient green office buildings, including the Hearst Tower among others. Mayor Bill de Blasio has committed to an 80% reduction in greenhouse gas emissions between 2014 and 2050 to reduce the city's contributions to climate change, beginning with a comprehensive "Green Buildings" plan.

What legal case sought to compel the Environmental Protection Agency to regular greenhouse gases?
Massachusetts v. Environmental Protection Agency