I found the following photo on Flickr, using a search for the “Diwali” tag (most recent):
The caption on Flickr is “Behold Srivathsan, the Magician of Fire.” If you click on the image and login to Flickr, you can see a larger version of the photo. Is it just your usual fireworks, or is something unuusal going on? What is up with the horizontal streak of light across the frame?
Whatever the case, I think it’s safe to say that this is the kind of thing that is pretty much “only in India.”