Before fossil fuels our cities were ankle-deep in horse shit, and when a horse died the owner dumped the carcass in the river. Some level of pollution is in inescapable price of civilization. We shouldn't be reckless or wanton about it but it's unreasonable and uneconomic to ever clean up all of the mess.

But you don’t know the cleanup cost yet, so how can you put a dollar amount on the subsidy?