Boil the potatoes in salted water (do not make it mushy), drain and keep aside.
Cook the chickpeas in salted water, drain and keep aside.
In a large pan, heat oil and crackle mustard seeds.
Reduce heat and add all the powdered spices and sauté for 30 seconds.
Add the potatoes and chickpeas; combine well and season with salt if necessary.
Cook for 10 minutes on low heat till the spices combine well with the potatoes and chickpeas.
Remove to serving dish, drizzle with yoghurt and garnish with chopped coriander leaves.