"The vast majority of Chad's 10 million people depend on subsistence agriculture for their livelihoods. Living standards are some of the lowest in the world. Yet the country has one major source of wealth - oil - and it has only started to be tapped in the last few years.
"As so often in Africa, political tensions are in part a scramble for who gets the income from mineral wealth. Chad has been exporting oil on a significant scale since 2003.
"Campaigners say Chad has become yet another African country where mineral wealth is contributing to instability and making life worse for most people, rather than bringing them higher living standards.
"Rows over who gets the benefit from oil and mineral exports are major factors behind conflicts in Nigeria's Delta region, Angola, the Democratic Republic of Congo and numerous other African nations. No wonder commentators have begun referring to the 'curse of oil'."