Heat oil in a large saucepan on medium. Cook onion, carrot and celery for 5 minutes, stirring occasionally, until beginning to soften. Add pumpkin and cook for 5 minutes.
Add stock and 2 cups water and bring to boil. Simmer, covered, for 15 minutes. Add chickpeas and simmer for another 2 minutes. Add finely chopped garlic and basil and season to taste. Rub toasted bread with halved garlic clove and serve with soup.