Delhi on Diwali is about as happy a city as any other metro but it is certainly the noisiest and smokiest.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/delhi-smokiest-and-noisiest-diwali-out-7-metros-says-survey
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/india-today-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/cse
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/festival
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/diwali
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/noise-pollution
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/environment
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/bangalore-d
[11] http://admin.indiaenvironmentportal.org.in/category/thesaurus/chennai-d
[12] http://admin.indiaenvironmentportal.org.in/category/thesaurus/mumbai
[13] http://admin.indiaenvironmentportal.org.in/category/thesaurus/kolkata
[14] http://admin.indiaenvironmentportal.org.in/category/thesaurus/central-pollution-control-board-cpcb
[15] http://admin.indiaenvironmentportal.org.in/category/thesaurus/health-effects
[16] http://admin.indiaenvironmentportal.org.in/category/thesaurus/heart-diseases
[17] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-quality-monitoring
[18] http://admin.indiaenvironmentportal.org.in/category/thesaurus/rspm-pm-10
[19] http://admin.indiaenvironmentportal.org.in/category/thesaurus/nitrogen-dioxide