Cut the ginger into thin strips and bring to a boil in the water, along with the cloves, cardamom, cinnamon and sugar. After 5 minutes add the milk. When it boils again, add the tea and cook for another 3 minutes. Be careful, that tends to boil over.
Finally, strain through a sieve into a cup and add sugar if necessary.
I had a local explain the recipe to me in Nepal. It is especially important that the spices boil for at least 5 minutes before milk and tea are added. Only then does the Masala Chai taste as strong as on vacation.
If you don`t put a lid on the pot, you end up with about the same amount of chai as you used to start with.