Thick fog and haze that envelops the city every morning and evening is an indicator of high pollution levels in the city.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/high-pollution-level-makes-city-colder-during-day
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/times-india-kanpur-0
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/uttar-pradesh
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/kanpur-t
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/state-pollution-control-board-spcb-0
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/cold-wave