Heat oil in a large saucepan over medium heat. Saute onions, carrots, and garlic until tender. Stir in green pepper, red pepper, celery, and chili powder. Cook until vegetables are tender, about 6 minutes.
Stir in mushrooms, and cook 4 minutes. Stir in tomatoes, kidney beans, and corn. Season with cumin, oregano, and basil. Bring to a boil, and reduce heat to medium. Cover, and simmer for 20 minutes, stirring occasionally.
