The pavements are choked with hawkers and the air is toxic
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/calcuttas-darkness-visible
[2] http://admin.indiaenvironmentportal.org.in/category/author/subrata-roy
[3] http://admin.indiaenvironmentportal.org.in/category/newspaper/business-india-mumbai
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/vehicular-pollution
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/west-bengal
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/calcutta-t