This is not a national movement yet, I thought it would be interesting to introduce to you some of these small movements that are planned and implemented for good goals and intentions
What the poster says is
"9월 10일(월)은 자동차를 두고 나오세요"
= Leave your cars at home on the 10th of September(Monday)
9월 10일은 서울버스 무료 탑승 (오전 9시까지)
= On September 10th, you can ride the buses in Seoul for free (until 9 a.m.)
http://carfreeday.or.kr is their website, and they've been doing this campaign for three now and I think it's a very impressive effort!
Their goals are
1) to reduce to the use of cars by 20% in Seoul
2) to reduce the total amount of traffic in the city by 30%
and to remind people of the importance of clean air
I want to participate, but I don't really have to do anything because I don't have a car ---- ^_^;