There are enough information in wiki and google (link and description below) about Nemmara Vela, that I have nothing more to add here. There are some pictures that are posted in sequence of events.
https://en.wikipedia.org/wiki/Nenmara_Vallanghy_Vela
The fireworks are so loud that it is called as Asia's loudest firework, arguably in the whole world. Nemmara vallanghy is also known as velakaluda vela, and its celebrated as equivalent as Thrissur Pooram.
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Nenmara Vallanghy Vela.
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Nenmara Vallanghy Vela.
"Anachamayam" are decorative items for the elephants that are paraded during the festival. Every year, these are displayed a day before the final day of the festival and inaugurated by prominent personalities.
Later that evening, we have a small "melam" followed by a sample of fireworks for next day.
On the main festival day, "thidambu" which is the representation of the deity is placed on top of the lead elephant followed by "Panchavadyam".
All decorated elephants are paraded to the temple, which is followed by fireworks. This repeats again at night.
