Wash, peel, and grate cucumber. Taste the cucumber before grating, if it has a bitter or has sour taste, then don't use it. If using English or Persian cucumber, peel, and grate. If using regular cucumbers, slice lengthwise and scrape out seeds using a spoon. Then grate the cucumber.
Now in a bowl add whisked yogurt, salt, roasted ground cumin, chaat masala, cilantro leaves, green chili (optional), grated cucumber, and mix it well.
Transfer to a serving bowl. Remove the slit green chili, if added. Garnish with roasted cumin powder, red chili powder, and mint leaves. And it's ready, have it immediately or refrigerate before serving.