The Supreme Court sought to know which chemicals should not be used beyond a limit in the firecrackers and observed that guidelines on this have to be laid down.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/sc-mulls-over-norms-pollution-light-emitting-crackers
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/indian-express-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/supreme-court
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/central-pollution-control-board-cpcb
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/diwali
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/festival
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution-control