The mixture shortens the life of the generator, however, and can make pollution even worse.

Mexico City has a reputation for some of the world's worst pollution.

Only the Los Angeles basin, he said, has worse pollution.

If you want to see the likely result go look at some of the worst pollution on the planet in the old soviet bloc.

London is nowhere near the worse for pollution among big cities.

Texas has seen some of the worst pollution.

But this was hardly the worst pollution he saw there.

But the worst pollution is right in town.

Only the mortality from lung cancer and cardiopulmonary disease were increased in the areas with the worst pollution.