WASHINGTON — The Environmental Protection Agency proposed tougher new limits on Tuesday on smokestack emissions from nearly two dozen states that burden downwind areas with air pollution from power plants they can’t control.

At the same time, the EPA moved to remove two states – South Carolina and Florida – from the “good neighbor” rules, saying they don’t contribute significant amounts of smog to other states. The EPA proposal came as Republicans in Congress moved to block President Obama’s plan to force steep cuts in greenhouse gas emissions from U.S. power plants.

The Senate approved two Republican-sponsored resolutions disapproving the power-plant rules and rendering them inoperative. The measures were both approved, 52-46, Tuesday under the little-used Congressional Review Act, which allows Congress to block executive actions it considers onerous with simple majority votes. The maneuver is subject to a presidential veto and has rarely been successful in overturning executive branch rules.

Sen. Susan Collins, R-Maine, and Sen. Angus King, I-Maine, both opposed both resolutions.

The EPA’s proposal on downwind pollution follows a federal appeals court ruling this summer that upheld the agency’s right to impose the clean-air standards, which block states from adding to air pollution in other localities.

The rule applies mostly to states in the South and Midwest that contribute to soot and smog along the East Coast.

Under the EPA’s proposal, states would have to comply with air quality standards for ozone, or smog, set by the George W. Bush administration in 2008. Current rules are based on pollution standards developed in the late 1990s.

“This update will help protect the health and lives of millions of Americans by reducing exposure to ozone pollution, which is linked to serious public health effects including reduced lung function, asthma … and early death from respiratory and cardiovascular causes,” EPA Administrator Gina McCarthy said in a statement.

The proposal reinforces the obligations states have to address air pollution that is carried across state lines, McCarthy said.

Senate Majority Leader Mitch McConnell of Kentucky focused on the climate rule. He said Obama was “trying to impose deeply regressive energy regulations that would eliminate good-paying jobs, punish the poor and make it even harder for Kentuckians to put food on the table.”

The Senate votes came less than two weeks before Obama and other world leaders are slated to meet in Paris to finalize an agreement to cut carbon emissions worldwide.