Environmental deregulation refers to the systematic weakening, repeal, or non-enforcement of environmental laws and regulations. It can take many forms: rolling back emission limits, eliminating monitoring requirements, approving weaker state plans, reducing agency budgets, or reinterpreting legal authority. Proponents argue deregulation reduces business costs and promotes economic growth. Critics point out that pollution costs are shifted to public health — more asthma, more cancer, more developmental problems in children — and that these costs far exceed the compliance savings. The Trump administration's 2025-2026 environmental rollbacks, including MATS and the Good Neighbor Rule, represent the most aggressive federal environmental deregulation effort in EPA's history.