The building comes with the special set bonus. It produces happiness when not connected to any other buildings of the set, and additional happiness when connected to other Indian Fountain set buildings.
For more information see the Set Bonuses.
The Chhatri Garden comes with the special set bonus. When it is adjacent to other buildings belonging to the Indian Fountain Set the properties of the building are improved.
The Chhatri Garden will provide the following happiness. Base happiness will always be produced. Bonus happiness is determined by how many other unique Indian Fountain Set buildings it is connected to.