Delhi is 6th most polluted city in world: WHO
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/pollution-dipped-2017-says-environment-ministry
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/hindu-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/who
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/central-pollution-control-board-cpcb
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-quality-monitoring
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/pm-25
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/rspm-pm-10
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/ministry-environment-and-forests-moef