1Peel and dice the potatoes into small cubes.
Chop the tomatoes and onions finely.
Mince the garlic and grate the ginger.
Heat the vegetable oil in a large pan over medium heat.
Add the cumin seeds and mustard seeds to the hot oil and let them splutter.
Add the chopped onions and sauté until they turn golden brown.
Add the minced garlic and grated ginger, and sauté for another minute.
Stir in the turmeric powder, red chili powder, and salt.
Add the chopped tomatoes and cook until they soften.
Add the diced potatoes and mix well to coat them with the spices.
Pour in the water and bring the mixture to a boil.
Reduce the heat, cover the pan, and let it simmer until the potatoes are cooked through.
Stir in the garam masala and sliced green chilies.
Cook for another 2-3 minutes, then remove from heat.
Garnish with fresh coriander before serving.