Peel mangoes. Take mangoes in a blender and puree till smooth. Set aside.
Heat water, bring it to a boil. Once it boils, add tea powder and boil for 3 mins. Add sugar and mix well. Take it off the heat. Cover and let it steep for 10 mins. Add lemon juice to this and strain the mixture. Set aside in fridge so it gets cold.
Mix tea mix and mango puree. mix well. Add more cold water as needed.
Take a serving glass, fill with ice cubes. Pour the tea and serve immediately.