Heat oil in a deep bottomed pan on a medium flame. Add mustard seeds, allow them to splutter. Add cumin seeds and curry leaves sauté for a minute.
Add onions and green chillies and sauté them for 5 minutes.
Once the onions are cooked, add drumstick pieces, turmeric powder, red chilli powder and salt.
Add one cup of water and cover with a lid and allow the drumsticks to cook under a low flame.
Once the drumsticks are cooked and the gravy becomes thick, remove from the flame and transfer to serving bowl.