Air pollution is dependent on several factors like industries, aviation, railways and construction activities.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/supreme-court-what-steps-taken-ban-china-crackers
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/asian-age-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/delhi
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/china
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/supreme-court
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution-control
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/diwali
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/festival