Data source: https://satp.org/conflict-maps/india India Conflict Map April 2019 (2018 data) from the South Asian Terrorism Portal
This is a derivative work of File:India map Naxal Left-wing violence or activity affected districts 2013.SVG, available on wikimedia commons. The data and coloring has been updated in the above map to reflect 2018 information, as accessed in October 2021.
Severely affected = 50+ casualties/year
Moderately affected = 11-50 casualties/year

Marginally affected = 1-10 casualties/year
Own work
Ganesha811