(NEXSTAR) — How clean are the air and water in your state?

Using 2021 data, U.S. News and World Reports’ feature on the “Best States” has ranked U.S. states on several metrics, including economics, education and health care. The listing also measures natural environment, which is based on a state’s air/water quality and pollution levels.

Pollution was determined based on air and water emissions from industry and utilities, and overall measures to long-term human health effects, using information from the Environmental Protection Agency.

Below are the most polluted (no. 50-40) and least polluted (no. 10-1) in U.S. News’ Pollution Rankings.

States with the worst pollution

50. Louisiana

49. Nevada

48. Indiana

47. Delaware

46. Utah

45. Ohio

44. Oregon

43. Tennessee

42. Illinois

41. Alabama

40. Texas

Louisiana ranks dead last, coming in as the most-polluted state in the U.S., according to EPA information.

A January 2022 study by Tulane University found very high incidences of cancer in Louisiana, the second-highest in the U.S. At least 85 cancer cases per year in the state were due to exposure to high levels of air pollution, the study found. Authors included data for neighborhoods in an area between Baton Rouge and New Orleans, which is locally known as “Cancer Alley.”

The state of Nevada ranks as the second-most polluted state, according to EPA information. Just last year, Nevada ranked among the “unhealthiest” states for air quality in the American Lung Association’s State of the Air report.

At that time, Melissa Ramos, manager of the Nevada ALA’s Clean Air Advocacy, said the Classic Car loophole was partly to blame for the state’s high emissions. Under the state’s Classic Vehicle Insurance policies, vehicles bearing certain license plates are exempt from emissions testing. Some tightening of the laws on classic vehicles is coming Jan. 1, 2023, however.

The least polluted states

10. Idaho

9. Colorado

8. Maine

7. Rhode Island

6. California

5. Wyoming

4. New Mexico

3. South Dakota

2. New Hampshire

1. Vermont

The state of Vermont is aware of its relatively good bill of health.

The Vermont Agency of Natural Resources writes that “Vermont’s air quality is considered to be among the best in the nation.” The agency notes, however, that Vermont’s air is not pollutant-free.

Interesting: Even though California ranks sixth among the least polluted states, many of its cities rank among America’s most polluted. Research from the American Lung Association ranked cities by ozone pollution, year-round particle pollution, and short-term particle pollution. California areas that ranked in the ALA’s top 10 most polluted cities in all three pollution categories include Los Angeles-Long Beach, Bakersfield, Fresno-Madera-Hanford, and Sacramento-Roseville.

Pollutants

Six common air pollutants identified and regulated by the EPA are carbon monoxide, lead, nitrogen oxides, ground-level ozone, particle pollution (also called “particulate matter”), and sulfur oxides. Other air pollutants include asbestos, fuel oils and kerosene, and benzene.