Vermont has the lowest level of pollution and Louisiana has the worst level according to US News.

State Pollution Rankings | US News Best States

1. Vermont

2. New Hampshire

3. South Dakota

4. New Mexico

5. Wyoming

6. California

7. Rhode Island

8. Maine

9. Colorado

10. Idaho

11. New York

12. Nebraska

13. Hawaii

14. Minnesota

15. Montana

16. Maryland

17. Massachusetts

18. Washington

19. North Dakota

20. Wisconsin

21. Arizona

22. Oklahoma

23. Kansas

24. Missouri

25. Iowa

26. Georgia

27. Florida

28. Mississippi

29. Alaska

30. Connecticut

31. North Carolina

32. Virginia

33. South Carolina

34. Michigan

35. Kentucky

36. Arkansas

37. West Virginia

38. New Jersey

39. Pennsylvania

40. Texas

41. Alabama

42. Illinois

43. Tennessee

44. Oregon

45. Ohio

46. Utah

47. Delaware

48. Indiana

49. Nevada

50. Louisiana