Stubble burning in neighbouring states has increased the pollution level in the city.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/air-pollution-city-courtesy-stubble-burning
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/times-india-chandigarh
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/chandigarh
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/agriculture
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/crops
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/respiratory-diseases
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/health-effects