lot of messages on board have been dealing with divide between north and south india. in this regard, important to consider seminal work by respected sir, dr. g.v.s srinicas, title is 'return of the native, study of societal divide in an anthropologically diverse country' essentially, respected professor is saying that because india has limited resources and very great population, it is only logical that people will group together according to differences per their genetic pools, in an attempt to compete for limited housing, jobs, money etc. dr. srinicas says that this phenomenon is especially prevalent in expatriate community when people from india will tend to stay in their respective gene pools rather than mingle with others, because they are maybe feeling threatened by caucasian peoples (whites). therefore, mallu will talk only to mallu, and punjabi only to punjabi. please read book for further details, it is available by penguin publishers in india