In a large pot, saute the onion and all of the peppers in oil for 5 minutes to soften.
Add the pumpkin and garlic and saute for an additional 5 minutes stirring often.
Add the vegetable broth and bring the mixture to a boil. Cover the pot, reduce the heat to low, and simmer for 25-30 minutes or until the pumpkin is just tender.
In a food processor (or blender) place 3/4 C. of the cut corn, add 1 C. of the cooking liquid from the pot, and process to form a chunky puree.
Add the pureed mixture, the remaining corn, chili powder, cumin, salt, and pepper to the pot, and simmer the soup an additional 5 minutes.
Add the remaining ingredients and stir well to combine.