Heat oil in a pressure cooker and fry the onion till translucent.
Add the mutton pieces and ginger garlic paste and cook till all the water dries up.
Add the tomatoes, red chili powder, coriander powder, turmeric powder and salt and mix well. Pour 1 cup of water and close the lid of the cooker and cook till the mutton is tender, about 15 minutes.
Allow the steam to escape and add the cut drumsticks and pour another cup of water and cook till the drumsticks are cooked.
Notes
Be careful not to overcook the drumsticks as they will fall apart.