London has a live tracker measuring each breach of hourly levels of toxic nitrogen dioxide and is accordingly shifting clean buses onto the most polluted routes, and Delhi has tried out everything
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/how-polluted-chennai%E2%80%99s-air-we-may-not-know
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/times-india-chennai
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/tamil-nadu
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/chennai-t
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/state-pollution-control-board-spcb-0
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/pm-25
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/health-effects