In a blender or food processor, combine mint, cilantro, garlic, ginger, onion, green chili, yogurt, sugar, salt, lemon juice, and cumin seeds. Blend for a few seconds, then add water and blend again until smooth. Adjust the water and salt to taste. Refrigerate the chutney until ready to serve.
1 cup mint, 1 cup cilantro, 4 garlic cloves, 1 inch ginger,, 1/4 piece red onion, 1 green chili, 2 tablespoons full fat yogurt, 1/2 teaspoon granulated sugar or jaggery, 1/2 teaspoon salt,, 1 teaspoon roasted cumin seeds, 1 tablespoon lemon juice