In a saucepan, combine the lentils, onions, garlic, and water. Cover, bring to a boil, then reduce the heat and simmer for 30 to 40 minutes, until the lentils are tender but not mushy.
Meanwhile, combine the bell peppers, celery, and red onions in a nonreactive bowl. When the lentils are cooked, drain and add them, while hot, to the bowl. Stir and set aside at room temperature for 15 minutes.
In a separate bowl, combine the yogurt, chutney, curry powder, red onion, and lime juice. Stir the yogurt mixture into the lentils and serve.