They do not contain harmful chemicals that would cause air pollution.  Components are replaced with others that are less dangerous and less harmful to the atmosphere.  The idea was carried forward by a network of CSIR labs.  The team came up with 3-4 formulations and looked at 30-40% of active materials which reduce particulate matter.  Potential sound-emitting functional prototypes that do not emit sulphur dioxide were also developed.  These crackers are named as Safe Water Releaser (SWAS), Safe Thermite Cracker (STAR) and Safe Minimal Aluminium (SAFAL).  These have the unique property of releasing water vapour and/or air as dust suppressant and diluent for gaseous emissions.