Heat the vegetable oil over medium-high heat in a heavy soup pot. Add the onion, ginger and garlic; saute for 5 minutes. Add the curry and honey; saute 2 minutes. Add the carrots, broth, and salt. Bring the soup to a boil, then lower it to a simmer. Cook the soup for about 30 minutes. Remove the soup from the heat and stir in the yogurt. Transfer the soup, in batches, to a blender and puree until smooth. Serve hot or chilled.