Firstly, the local underprivileged people will not have the money to buy the book. Secondly, they cannot read English. In my opinion, if any book is intend to do good for local people it should be written in a local language. If you write a local story or an issue in English, it is only for the privileged population. The English literature written in South Asia is mostly related to Western thoughts and ideas or targeted at audiences with a Western mentality.
Languages have their own cultures and laws of expression.
While Indian authors writing in English are winning accolades in the Western world, it is wrong to presume that the quality of local literature is in any way inferior to that produced in English. In fact, some of the best works that I have read are written by contemporary Hindi authors. Biju Rao, India I strongly believe that the Sub-continent has some of the best literature in the world. Poetry in Urdu is so classical and rhythmic that you will ruin it if you try to translate it into English. India and Pakistan is the home of great poets like Ghalib, Iqbal, Mir and many more.