[Editor's Note: Updated with comments from Dow, the Environmental Defense Fund and more.]

Bowing to pressure from business groups, President Barack Obama put the brakes on plans to toughen smog standards and ordered the Environmental Protection Agency this morning to withdraw its draft of updated rules.

The Washington Post's early report on Obama's about-face spread the news as the world inside the Beltway began slipping away for the long Labor Day weekend. Nevertheless, the response from environmental groups and other advocates of the stricter regulations was swift and sharp.

"The Obama administration is caving to big polluters at the expense of protecting the air we breathe," said Gene Karpinski, president of the League of Conservation Voters, in a statement issued in Washington, D.C. "This is a huge win for corporate polluters and huge loss for public health."

The Natural Resources Defense Council also weighed in.

"The White House is siding with corporate polluters over the American people," said NRDC President Frances Beinecke. "The Clean Air Act clearly requires the Environmental Protection Agency to set protective standards against smog-based on science and the law. The White House now has polluted that process with politics.

"Our public officials, including in the White House, serve to protect us from harm. They need to get on with doing their jobs. Inaction cannot be an option when it comes to ensuring a healthy and prosperous America."

Business groups had called for the delay of new regulations, saying that new pollution controls would be too expensive to put in place in an economic climate that remains poor.

"The signal today was that message is being heard," said Jack Gerard, president of the American Petroleum Institute, according to a report from Bloomberg.

The proposed EPA regulations would have tightened rules for ground-level ozone set by the Bush administration in 2008. Ground-level ozone, the main component in smog, is formed by emissions from factories, power plants, cars and other sources, like landfills, when they react with sunlight.

The standards for ground-level ozone are due for an update in 2013. But in January 2010 EPA Administrator Lisa Jackson said the rules on the books were not strict enough, given that the emission levels permitted by the 2008 regulations were significantly higher than those recommended by the agency's scientific advisory committee.

Here's how Obama explained his decision in a statement this morning:

"After careful consideration, I have requested that Administrator Jackson withdraw the draft Ozone National Ambient Air Quality Standards at this time. Work is already underway to update a 2006 review of the science that will result in the reconsideration of the ozone standard in 2013.  Ultimately, I did not support asking state and local governments to begin implementing a new standard that will soon be reconsidered."

The American Lung Association threatened to go to court.

"For two years the administration dragged its feet by delaying its decision, unnecessarily putting lives at risk," said a statement from American Lung Association President and CEO Charles D. Connor. "Its final decision not to enact a more protective ozone health standard is jeopardizing the health of millions of Americans, which is inexcusable.

"The American Lung Association now intends to revive its participation in litigation with the administration, which was suspended following numerous assurances that the administration was going to complete this reconsideration and obey the law."

Next Page: What Dow and the Environmental Defense Fund had to say.