A recent UNESCO report indicates that India has the largest number of endangered languages in the world. A matter of concern, besides the absolute numbers, is the distribution of these endangered languages across number of speakers. The languages under threat include both scheduled, non-scheduled as well as official languages of some of the states.
Links:
[1] http://admin.indiaenvironmentportal.org.in/feature-article/endangered-languages-some-concerns
[2] http://admin.indiaenvironmentportal.org.in/category/author/papia-sengupta
[3] http://admin.indiaenvironmentportal.org.in/category/journal/economic-and-political-weekly
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/atlas-0
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/unesco
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/society-and-history
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/india
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/statistics