Because of there natural resources like iron and coal.
maybe 5-6 hours a day too much can be bad . . .. . . . .
Answer:
How I’m I supposed to know
Explanation:
Idk
The enactment of the Clean Air Act of 1970 (1970 CAA) resulted in a major shift in the federal government's role in air pollution control. This legislation authorized the development of comprehensive federal and state regulations to limit emissions from both stationary (industrial) sources and mobile sources.
