Heat olive oil in a large pot over medium heat. Add diced onions and sauté for about 3-4 minutes until softened.
Add minced garlic, diced carrots, celery, and bell pepper. Cook for another 5-7 minutes until the vegetables begin to soften.
Stir in the diced zucchini, and cook for an additional 2-3 minutes.
Add the chickpeas, vegetable broth, canned diced tomatoes, turmeric, cumin, salt, and black pepper. Bring the mixture to a boil.
Once boiling, reduce the heat and let the soup simmer for 20 minutes, stirring occasionally.
If desired, use a blender to purée part of the soup for a creamier texture before adding the spinach.
Stir in the spinach and let it cook for an additional 2-3 minutes until wilted.
Taste and adjust seasoning if necessary. Serve warm with a drizzle of lemon juice on top.