Arun (Singapore)
Congestion Charging is almost proven not to work all by itself. It has to come backed up with extensive public transport systems. Singapore has a decent public transport system which is why Congestion Charging works. Singapore has a metro stop almost every two blocks (in the central districts) and buses every 5 minutes to feed them. The inherent solution itself comes with the way the cities are designed so that people travel less. China could solve half their problem with ramping up the density of residential areas around their work places.