Child labour in Sivakasi: I am no expert and don't know the current situation. This has been highlighted a lot over the years and I have seen reports of action being taken against the culprits. Child labour, if it still exists, is a symptom, not the cause. The children work because their parents are too poor to continue to send them to school. The solution is to lift the families out of poverty AND educate them about the importance of keeping their kids in school. Accomplish that and watch the problem go away, if not the people will just send their children to work elsewhere.
Noise/atmospheric pollution: This argument has more merit as the increase in the SPM count and other gases cause problems to those having respiratory issues. The other constituent that suffers the most are the animals that are mortally scared of the loud noise. Some steps have been taken in this direction by banning really loud crackers. I've also seen a gradual shift towards the visual aspect of fireworks over the years.
There are quite a few positive aspects of Diwali
Awareness of tradition: Diwali is one of the fun ways to get children to understand about Indian culture and tradition
Boost to the economy: The spending that happens during Diwali may seem vulgar to the PC masses. But, it is this kind of spending that stimulates the economy and creates jobs for the poorer classes.
Let's put this bullcrap aside and celebrate Diwali in the traditional way. Happy Diwali everyone.