Getting headaches during Diwali? Firecracker smoke, poor sleep and dehydration could be triggers. A doctor explains the symptoms you shouldn. New Delhi: Diwali is almost here, and everyone is busy planning parties, shopping for gifts and preparing for celebrations. But if you've ever experienced a migraine or unexplained heaviness in your head after spending time outdoors during Diwali, firecracker smoke could be one of the reasons.