Scrub celery roots well. Cut of the top and bottom of the bulb. Remove skin. Keep them in the water with 1 tbsp of lemon juice to prevent darkening. Wash and drain the leaves and cut them two to three pieces. Wash potatoes and carrots. Peel potatoes and cut them into cubes. Peel the carrots and slice. Cut the onion into halves and slice both thinly. Take olive oil and onion into small pot. Turn the heat on medium. Saute onion. Add tomato and pepper paste into the pot and saute them for three-four minutes. Take the celery roots from the water and cut them into cubes. Add celery,celery leaves, potato, carrot, and boiling water. Stir and bring it to the boil.Add salt. Turn the heat down to low and simmer until celery cubes are soft. Serve it warm.