I'd say a lack of education and corruption. A self centered view of the world creates wealth for few and leaves many behind.
I think its also something historicall as many countries have been exploited and have often been left alone to repair the damages themselves which they were not able to handle.
The common cause of poverty is corruption especially in our government official they are strong involved in corruption.second is the un-employement, terrorism, drugs. This are the main reason why we suffer poverty.