It is a programme that helps children of one state meet and learn about children of other states, so that they understand that all of them belong to one nation.
Renu explains it in the text: “It is to know that we all belong to one nation and that is the bond we share. And our unity in diversity makes us the most wonderful country in the world.”
The note on page 140 adds the official aim — states and Union Territories are paired with each other, and the paired states share their languages, food, music, dance, handicrafts, sports, literature, festivals and paintings.