The London 'Toxicity Charge' / 'T-charge' / Ultra-Low Emission Zone (ULEZ)

Outside St Pancs/Kings Cross, empty taxis, parked up, pretty much all with engines running.

Yeah, I find that a bit annoying as well. At times there must be well over 100 black cabs from o/s St Pancras all the way back to York Rd. All idling.