Heat olive oil in a large pot over medium heat.
Add diced onions and cook until translucent, about 5 minutes.
Stir in minced garlic and cook for an additional minute.
Add carrots and celery, cooking for about 5-7 minutes until softened.
Add bell pepper and zucchini; cook for another 4-5 minutes.
Pour in the canned tomatoes with their juice.
Pour in the vegetable broth and bring to a simmer.
Stir in green beans, oregano, basil, salt, and pepper.
Simmer for 20-25 minutes until vegetables are tender.
Taste and adjust seasoning if necessary before serving.