A carbon sink is a system that absorbs carbon dioxide from the atmosphere.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/carbon-sink-target-india-looks-catchment-area-plan
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/indian-express-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/carbon-sinks
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/carbon-dioxide
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/atmosphere
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/cop-21-paris
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/groundwater-recharge
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/forests