Place yogurt, ½ cup water, salt and roasted cumin powder in a jug. Whisk together till smooth. Add more water if a more liquid consistency is preferred. Taste and add more salt or cumin seeds as required. If you feel the lassi is too sour, add a tablespoon of sugar to balance it out. The lassi can also be made in a blender.
Pour into glasses and add ice cubes. Garnish with roasted cumin powder (bhuna zeera) and serve cold.