Take 500 grams of watermelon, remove the seeds, and cut it into small cubes. Keep the watermelon cubes aside.
In a mixing bowl, add 250 grams of fresh curd (dahi) and whisk it until smooth.
Add 1/2 teaspoon of roasted cumin powder (jeera powder), 1/4 teaspoon of black salt (kala namak), and 1/4 teaspoon of regular salt to the whisked curd. Mix well.
Gently fold in the watermelon cubes into the curd mixture.
Refrigerate the watermelon raita for at least 30 minutes to allow the flavors to blend.
Before serving, garnish with a few chopped mint leaves (pudina) and a pinch of red chili powder (optional).