Heat water in a sauce pan. Add the moong dal and chopped vegetables to it.
Boil or pressure cook until well cooked.
Puree either with a hand blender or in a grinder jar. Transfer the puree to a sauce pan (if using blender). Dilute with water.
Season with black pepper and give it a boil. Turn off the flame.
Add few drops of lemon juice if desired. Serve warm.