jtr,
No it isn't an Asian thing.The original push backs when the airport opened on single runway they were always red/blue.Generally we had red push for one runway,and blue for the other.We soon discovered that a little mixing could improve the capacity off stands.The Green only came later and it was a push and tow forward.I think the idea was it was for CPA/Dragonair so green was appropriate.The hardest problem was getting pilots to readback the colour.I've had push two,push approved,push when? But it does really work.
