[polymuser]

I have a great idea for clean and green transportation!

[Red Badger]

That’s what they want to do! Go Back to the Future!..............

[Verginius Rufus]

When cars began to replace horse-drawn carriages in cities, people thought it would mean cleaner air. Horse droppings got chopped up by wheels and the bits got into the air.

I asked my father once if there were still a lot of horse-drawn carriages on the streets when he was young. He said yes, and that people would take the horse droppings and put them in their gardens for fertilizer.