The report says Indianapolis and South Bend rank among the 25 worst areas in the country for short-term particles in the air.

Maryland environmental officials filed a petition Wednesday asking the EPA to crack down on 19 coal plants in Indiana, Kentucky, Ohio, Pennsylvania and West Virginia.

A lawsuit could add Indiana to the Ozone Transport Region, a group of 11 states required by the EPA to reduce smog-causing pollutants.

They want a federal judge to force the EPA to add nine more states, including Indiana, to the group required by law to act together to reduce smog in the Northeast.

Five coal plants in Indiana ranked in the top 100 for both toxic and greenhouse gas pollution - more than any other state.

Air quality may become unhealthy for individuals, especially active children, the elderly, and anyone suffering from lung disease or other serious health problems.