I'm seeing that there are lots of variations on using yogurt. This is good! Knowledge base in the kitchen is cool.Raita is an Indian dish; basically yoghurt with herbs ( coriander leaf, mint, maybe dill)and diced cucumber. Occasionally, a pinch of cumin.
There are many variants, however: spinach, potato, daikon radish.
The idea of a raita is a cooling dish, which offsets the spices in the main dishes. There's no such thing as a "salad"in Indian cuisine.