First you need to mix Yogurt and water keep it aside.
Now take a large bowl mix all these maida,salt,cumin seeds,chopped ginger,chopped green chillies and butter milk make it into vada batter consistency .Keep it aside for 1 hour.
Heat oil to fry, make into small round bondas and put in to the oil, cook in a very slow flame.
Remove once it is golden brown colour.
Serve it with coconut chutney