The biological water quality of Narmada river is under category B-C, which is below average. The reason for the degradation of water quality is mainly due to human activities, including religious, recreational and agricultural.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/narmadas-polluted-water-unfit-humans
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/pioneer-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-pollution
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/river-pollution
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/narmada
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-quality
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/state-pollution-control-board-spcb-0
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/madhya-pradesh
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/hoshangabad-d
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/narsimhapur-d