Hi from London:
The centre is much more pleasant to walk in, as are most places in the zone.
Pollution is much, much better: if you came to London and travelled on the underground you would have black snot when you blew your nose, this hasn't been the case for a few years now.
I hope NY gets the sake improvements.
Travel of low-income people also declined significantly while high-income travel did not. So quite literally the London congestion pricing got the poor off the zones.
London has changed for the better for sure but black snot on the tube hasn't changed at all. I get it from 20 minutes on any deep line like the Victoria. It's from train brake dust, nothing to do with vehicle emissions.