Around 70 north-bound trains, including Rajdhani services, were delayed, while around 30 others were rescheduled due to fog.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/air-quality-%E2%80%98severe%E2%80%99-dense-fog-engulfs-delhi
[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-quality-standards
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-quality-index-aqi
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/central-pollution-control-board-cpcb
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/pm-25
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/rspm-pm-10