Heat the water to 75–80°C / 167–176°F. Add the green tea bags and steep for 2–3 minutes only. Green tea over-extracts fast; longer steeping introduces bitterness and grassy notes. Remove the tea bags without squeezing.
While the tea is still warm, add the light brown sugar and stir until fully dissolved. Sweetening at this stage ensures even balance and avoids grainy texture later.
Add the lemon zest and orange zest to the sweetened green tea. Cover and let steep for 8–10 minutes to extract aromatic citrus oils without pushing acidity.
Strain the tea through a fine-mesh sieve into a bowl or large measuring jug, removing all zest. Let the citrus-infused green tea extract cool completely before assembling.
Pour the cooled extract into a large pitcher. Add the lemon juice, orange juice, fine sea salt, and ice-cold water. Stir gently until fully combined.
Refrigerate for 1–2 hours until fully cold and flavors are integrated.
Fill glasses with ice, pour over the green tea citrus drink, and garnish with lemon and orange slices.