Heat the water to 75–80°C (167–176°F), do not boil. Add the green tea bags and steep for 2–3 minutes maximum. Remove the tea bags without squeezing and let the tea cool to lukewarm.
In a small saucepan, combine the mango, sugar, and water. Bring to a gentle simmer over medium-low heat and cook for 8–10 minutes, just until the mango softens and releases aroma. Do not reduce or thicken.
Strain through a fine-mesh sieve into a bowl or measuring jug. Do not press the pulp. Discard the solids and let the syrup cool completely.
Add the deseeded chili slices to the warm tea and let infuse for 3–4 minutes only, just until a gentle warmth develops. Remove immediately. This is aroma and structure, not heat.
Stir 120–160 ml of the cooled mango syrup into the tea. Taste and adjust carefully — mango should be clean and present, never heavy.
Refrigerate for 1–2 hours until fully cold and integrated.
Fill glasses with ice, pour over the chilled mango iced green tea, and garnish with fresh mango cubes and optional deseeded chili slices.
