From Aol News
By SETH BORENSTEIN, AP
WASHINGTON -Pollution before the first Earth Day was not only visible, it was in your face: Cleveland’s Cuyahoga River caught fire. An oil spill fouled 30 miles of Southern California beaches. And thick smog choked many cities’ skies.
Not anymore.
On Thursday, 40 years after that first Earth Day in 1970, smog levels nationwide have dropped by about a quarter, and lead levels in the air are down more than 90 percent. Formerly fetid lakes and burning rivers are now open to swimmers.
The challenges to the planet today are largely invisible — and therefore tougher to tackle. Read complete article on Aol News