In a 2-quart saucepan, combine the ginger with 4 cups of water. Bring to a boil, reduce the heat, and simmer 20 minutes.
Stir in the honey. Place the tea or tea bags in the liquid and steep for 3 minutes.
Add the skim milk and bring to a boil. Remove from the heat, strain, and chill in an ice bath. Pour into an ice cream maker and follow the manufacturer's
instructions. Alternatively, pour into a shallow freezer-proof pan and freeze for 2 hours. Break up the chai with a fork and refreeze for 2 hours.
Spoon into the bowl of a food processor and process until smooth. Refreeze for 1 hour more. The chai will have the consistency of shaved ice.