The Environmental Protection Agency announced it will stop defending the rule finalized last year that set a stricter 9 micrograms per cubic meter standard for fine-particle pollution known as soot.The agency stated it lacked authority for these measures and joined a court challenge led by attorneys general from Kentucky and West Virginia, siding with business groups and 25 Republican-led states seeking to revert to the previous Obama-era standard.Critics warn this move threatens public health, while supporters like Michael Regan previously highlighted the rule's projected $46 billion in health benefits, including reduced asthma, hospital visits, and premature deaths.