Marinate the zucchini and the potatoes in salt and turmeric for 5 minutes. Then heat oil in a vessel and fry them for 5-6 minutes until golden. Remove and keep aside. In the remaining oil add the ginger paste, cumin, turmeric and chili powder. Fry for 2 minutes and add the tomatoes. Fry well for 5-6 minutes and add the vegetables. Add the sugar and water and cook until done. Garnish with chopped cilantro and serve with hot chapatis or rice.