That's a large question.
I think the general impression is that if you want to get cars off the road, you have to get bums in the seats of public transit systems, so the general impact is thousands of cars off the road and the greenhouse gas emissions that go with that.
I would say that whether it's the green line or any other public transit mode that's been delayed unjustifiably—because there are justifiable delays and then there are unjustifiable delays—in those cases you are talking about thousands and thousands of megatonnes of pollution that remain in the air that don't need to be there. Ultimately, delaying public transit delays our achievements.