Chaas is a post-meal, savory, lightly spiced, cool drink that rounds up a spicy, hot Gujarati meal. Almost watery, chaas is particularly welcomed in the hot, tropical climate of western Indian state of Gujarat. —Annada Rathi
Place yogurt in a bowl. Add water. Stir well with a whisk.
Add salt, cumin, and cilantro. Whisk once again. Generally, the chaas found in Gujarat is almost watery, which bodes well for the climate. You can adjust the water content depending on your preference.