Last week, the Trump administration delivered a catastrophic blow to U.S. climate policy by repealing the longstanding scientific finding that planet-warming pollution poses a danger to humans. Now comes the yearslong race through the courts.

The EPA repealed the key underpinning of greenhouse gas emission regulations. Now environmental and health advocates are taking the agency to court.

Birders inadvertently provided researchers at Loyola University with a key bit of documentation related to invasive species and microplastics.

In a reversal from previous years’ pollution reductions, the United States spewed 2.4% more heat-trapping gases from the burning of fossil fuels in 2025 than in the year before, researchers calculated in a study released Tuesday.

The plan, if finalized next year, would significantly reduce fuel economy requirements, which set rules on how far new vehicles need to travel on a gallon of gasoline, through the 2031 model year.

The proposal is opposed not only by business groups but also labor organizations, including the Chicago Federation of Labor, which are concerned that the measure would snarl new and expanding businesses in red tape, preventing them from creating new jobs.

A key split is whether the treaty should require cutting plastic production, with powerful oil-producing nations opposed; most plastic is made from fossil fuels. They say redesign, recycling and reuse can solve the problem, while other countries and some major companies say that’s not enough.

The National Weather Service issued an air quality alert for the city on Thursday and kept extending it through Sunday night. There was no alert Monday.

Smoke from Canadian wildfires settled over Chicago Thursday, with air quality reaching “unhealthy” levels for everyone. Air quality was far worse in parts of Canada closer to the fires.

The particles are likely the result of the degradation of plastic-filled objects such as carpet, curtains, furniture and textiles and the plastic parts of car interiors, according to the study published Wednesday in the journal PLOS One.

“My kids grew up smelling dead animals and rotting fish,” said Ljiljana Radocaj, a mother and resident of the 10th Ward. “It’s the most horrific smell — you can’t even describe it. You can just run from it.”

The EPA also proposed weakening a regulation that requires power plants to reduce emissions of mercury and other toxic pollutants that can harm brain development of young children and contribute to heart attacks and other health problems in adults.

Illinois Attorney General Kwame Raoul has announced a $4.8 million settlement with Trump International Hotel & Tower in Chicago, resolving environmental violations related to the building’s cooling system, which uses water drawn from the Chicago River.

The Environmental Protection Agency said Wednesday that it plans to weaken limits on some so-called forever chemicals in drinking water that were finalized last year, while maintaining standards for two common ones.

Illinois regulators are considering adopting a set of standards to improve air quality. The Illinois Pollution Control Board took hours of testimony Monday from environmental and other advocates.

At issue is the Sims Metal Management company in Pilsen, which was cited by state and federal officials for violating environmental laws. The company agreed to build new equipment to contain emissions from at the site.