Put the vegetable oil in a large heavy-based pan over a medium high heat. When hot, add the onion, ginger and garlic and cook for 8 minutes until the onions have softened and turned golden brown. Add the chicken and fry until colored.
Add the garam masala, cumin powder, ground turmeric and chili powder and fry for 2 minutes.
Add the chopped tomatoes, salt, green capsicum peppers and chili. Give everything a good stir together, then turn the heat down to low, cover and simmer gently for 15-20 minutes, or until the chicken is cooked through and tender.
