Heat olive oil in a large pot over medium heat.
Add chopped onion and sauté until translucent, about 5 minutes.
Stir in minced garlic and cook for another minute.
Add sliced carrots and diced celery, cooking for 5-7 minutes until softened.
Introduce diced zucchini and chopped bell pepper, stirring well.
Pour in vegetable broth and bring to a boil.
Add canned diced tomatoes with their juices.
Season with salt, pepper, and fresh herbs.
Reduce heat and simmer for 20 minutes.
Taste and adjust seasoning as necessary before serving.