Following a modest beginning in the early 90s, tea plantation has made a quantum jump in Kishanganj, the only district in the state where tea is grown and has thus put Bihar on the tea map of the country.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/hope-bihar-tea-trade-brews-kishanganj
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/times-india-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/agriculture
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/tea
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/trade
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/bihar
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/kishanganj-d