Heat water in a saucepan over medium-high heat.
Once the water comes to a boil, reduce the heat to low.
Add ginger and lemongrass leaves to it and let it simmer for 2-3 minutes.
Add tea leaves and sugar and again simmer for a minute.
Now increase the heat to medium-high.
Add milk and let the tea cook for another minute.
Stir frequently to prevent it from spilling over.
Strain using a tea strainer into 2 serving cups and serve immediately.