Heat the oil in a large saucepan over a medium heat. Add the onion and garlic and cook for a few minutes and then add the curry powder.
Cook for an extra 2 minutes and then add the carrots, celery and stock. Bring to the boil, reduce the heat, and simmer gently for about 30 minutes, or until the carrots are tender.
Allow to cool a little, then pure the mixture in batches in a blender, or with a hand-held liquidizer. Gently reheat the soup.
Season to taste with salt and freshly ground black pepper. Serve garnished with a dollop of goat's yogurt and a sprinkling of chives.