Boil Grapes: In a saucepan, add black grapes and water. Turn on the flame, bring it to a boil and cook on medium flame until soft and slightly mashed.
Dissolve Sugar: Add sugar, mix well and cook on medium flame until sugar is dissolved (about 3-4 minutes).
Add Spices: Add cumin seeds, chaat masala, black salt, dried ginger powder, and purple food color. Mix well and cook on low flame for a minute, then strain.
Mix Final Ingredients: Add pink salt and lemon juice to the strained mixture and mix well.
Serve: In a serving glass, add crushed ice, lemon slices, mint leaves, prepared syrup (3-4 tbsp), and carbonated/sparkling water. Stir and serve!