In a medium saucepan, bring 2 cups of water to a boil. Add the green tea leaves and baking soda. Boil for about 10 minutes, stirring occasionally, until the water reduces to about half. The mixture should turn a deep reddish-brown color.
Remove the saucepan from heat and let it cool slightly. Using a fine mesh strainer, strain the tea into a separate bowl, discarding the leaves.
Return the strained tea to the saucepan and add 4 cups of milk. Bring the mixture to a gentle boil over medium heat, stirring frequently.
Once it reaches a boil, reduce the heat and simmer for 5-10 minutes until the tea turns a beautiful pink color. If it doesn’t turn pink, whisk vigorously for a minute to aerate it.
Stir in the heavy cream, sugar, and ground cardamom. Adjust the sweetness to your preference. Simmer for an additional 2-3 minutes.
Remove from heat and let it cool slightly before serving.
Pour the chai into cups and garnish with chopped pistachios and almonds.