Refined white sugar is efficient and completely characterless. Jaggery — gur — is what sweetness tasted like before mills stripped it clean.
It's unrefined cane (or palm) sugar, set into blocks, cubes, or ground to powder, and it keeps a warm, caramel-molasses depth that plain sugar simply doesn't have.
How to use it
Use it the way you'd use sugar, with two small habits: add it at the end when there's hot milk involved, since it can split boiling milk, and taste as you go, because its sweetness reads a little differently.
Beyond that — chai, kheer, chikki, chutney, or just a cube after a meal, the way it's always been eaten.