Heat oil in a pan or a kadai.
Add cumin seeds and ginger-garlic paste.
Add sliced onions and saute, till they become transparent.
Add sliced tomatoes and cook, till done.
Add turmeric powder, coriander powder, cumin powder, garam masala, red chilly powder and salt.
Add the grated potatoes along with water and cook, till they become tender.
:- Add more water, if needed.
Add curd and mix well.
:- Do not boil.
:- Serve hot with rice along with pickle.