Why do people throw firecrackers at each other in Gujarat's Savarkundla on Diwali?

As part of a 100-year-old tradition, people in Gujarat's Savarkundla hurl 'ingoriya' firecrackers at each other on Diwali. The fight takes place between villagers of Savar and Kundla, which are separated by a small river. The crackers are made by stuffing gunpowder into 'ingoriya', a local fruit. Locals say that these firecrackers don't explode but only generate flames when fired.