Take yogurt in a bowl, add water and whisk lightly to make buttermilk.
Add freshly ground cumin powder, lime juice, salt, mix and keep aside.
Take oil in a pan for tempering.
When oil is hot, add mustard seeds, fenugreek seeds, ajwain and let the fenugreek seeds turn light brown.
Reduce the flame, add cumin seeds, asafoetida, stir and turn off the flame.
Add curry curry, green chilies, chopped cilantro let the chilies roast in the oil.
Pour it over buttermilk, stir and refrigerate until ready to serve.