DNA: Do green crackers not cause pollution?

People have only one option left for firecrackers on Diwali...and that option is green firecrackers...Delhi people don't even have this option...If you have gone to the market to buy firecrackers, then you will have to buy the firecrackers first. crackers would have been found to be costlier than the crackers...and when you would have asked the reason for them being expensive, the shopkeeper would have said that these are green crackers. That is why their price is higher. ..but what are these green crackers? And how are green crackers different from normal crackers?