For Kadhi: Mix curd, salt, turmeric powder, chilli powder, garam masala, and besan well. Add about 1 cup water so that the mixture is the consistency of lassi (buttermilk). Heat oil in a saucepan. Add cumin seeds and fry till they splutter. Add the onions and curry leaves. Fry for 2 minutes. Add curd mixture and bring to a boil gradually, stirring continuously. Reduce the flame to simmer. Add green chilles and simmer till kadhi is thickened, about 10 minutes.
For pakoda: Mix besan, salt, chilli powder and soda bicarb with water into a thick batter. Set aside for 5 minutes. Heat oil in a deep frying pan or kadhai. Take one heaped teaspoon of besan mixture at at time and deep fry until golden brown. Lay pakodas out on paper to drain. Add to hot kadhi 10 minutes before serving.