Place water in a saucepan over high heat. Once it comes to a boil, add tea-leaves or tea bag and cardamom. Reduce the heat to medium and gently allow this to simmer for a minute or two.
Add the milk and raise the heat back to high (or allow the milk to come to a simmer on its own).
As it begins to boil, the chai will rise in the saucepan. Remove the pan from heat before it reaches the top of the saucepan. Do this a few times to really develop the flavor while using a ladle to scoop and pour back the chai. Alternately, once it comes to a boil, lower the heat and allow it to simmer to desired strength (~3-5 minutes).
Pour this chai through a small sieve into your favorite cups and sweeten using sugar or honey.