Boil turnips in 5-6 cups water. mashed it with water when its tender .
Cut the chicken into 2-3inch pieces.Put the onions,garlic,ginger,salt, chili powder, ground coriander, chicken and 1,1/2cups water in a heavy based pot. cook for 10 to 15 minutes, or until the meat is half cook.
Add oil ,tomatoes and potatoes and cook for 5 to 10 minutes.
then mashed turnips with water.
and cook for 10 to 15 minutes .then sprinkle Garam Masala.