The green background symbolizes growth, harmony, freshness, and fertility; We are surrounded by the ability to grow. All we have to do is reach out and embrace it. The red & yellow, black & white figures represent diversity and tolerance. Our children are the key to peace and tolerance of: race, religion, physical, mental, and social diversity. The star, which is made up of the figures' legs, represents light. We can be a light for the world, if we choose. The five points on the star represent the continents. We are all part of one true race, the human race. The earth figure, which is directly in the center, represents our earthly home and all the blessings on it, which God has given us all to share and respect. The large blue circle engulfing the figures symbolizes peace and God's universal love. It also represents the unity that we can achieve if we reach out to one another in love. Blue symbolizes trust, loyalty, wisdom, confidence, intelligence, faith, truth, and heaven. The blue figure at the top represents God, who is the author & finisher of all things. God loves all of us equally and we should be striving to imitate that love (which is represented by the figures reaching out to each other).
Regarding the International Children's Day, it is widely celebrated on June 1. Children's Day had its origin in the World Conference for the Wellbeing of Children in Geneva in 1925. The June 1 date has a Chinese-USA origin - and nothing to do with Communism. In 1925, the Chinese consul-general in San Francisco gathered a number of Chinese orphans to celebrate the Dragon Boat Festival. This, of course, coincided with the conference mentioned above. June 1 somehow died out in the USA, only to be revived a couple of years ago. However, each country choses its own day to commemorate it.
The date, June 1st, has been adopted in the US as the official day. More than 30 states actively participate in the June 1st observance. The flag has been adopted by dozens of states and is being manufactured.