| A new study shows air pollution in some national parks is so bad it rivals the smog in major cities. |
| We have had several announcements about banning of air horns or double horns or multi-toned horns to check air pollution. |
| The survey also measured levels of air pollution, quality and quantity of drinking water and sewage. |
| Each of the millions of cars in the United States is potentially a source of air pollution. |
| The authorities are considering a ban on all cars manufactured prior to 1990 in an effort to fight air pollution. |
| Automobile exhaust fumes have become a major contributor to air pollution globally. |
