Using a mortar and pestle or the flat side of a knife, gently bruise the cardamom pods until they just crack open.
In a medium saucepan, combine the bruised cardamom pods, grated ginger, cloves, cinnamon stick, and 2 cups (480 ml) of water.
Bring the mixture to a rolling boil over medium-high heat and let it simmer for 5 minutes to infuse the water with the spices.
Add the milk and tea bags to the saucepan.
Bring the mixture back up to a boil, then immediately reduce the heat to low and simmer for 2-3 minutes. Be careful not to let it boil over.
Carefully strain the chai through a fine-mesh sieve into cups.
Serve immediately, with sugar on the side for everyone to sweeten as they wish.