Heat the oil over a medium heat and fry the onions, green chillies and cinnamon sticks until the onions are soft. Add the potatoes, and fry over a low heat for 6-8 minutes. Stir in the turmeric and chili powder, and add the water. Bring it to the boil, cover the pan and simmer for 6-8 minutes, until the potatoes are half cooked. Add the cabbage and salt, and mix well. Reduce the heat to the minimum setting, cover the pan and cook until the vegetables are tender (the cabbage should not be mushy). The finished dish should be fairly moist but not wet. If there is too much liquid left in the pan, remove the lid and let the liquid evaporate. Stir in the coriander leaves, add extra salt if necessary and serve.