Greater Indian Sphere.
Indian core: India proper
Fundamental colonies: Countries whose civilizations were fundamentally an Indian endeavour.
Brief colonies: Countries that were ruled by an Indian for a brief period of time.
Fundamentally Hindu/Buddhist: Countries whose civilizations were fundamentally Hindu/Buddhist, but no direct Indian rule.
Deep Influence: Countries that were significantly influenced by Indiian religion and philosophy.
Raided: Brief raids by Chachas and Pratiharas.
Explored: Countries that were visited by Indians in antiquity.