The channels, I am sure, will try for equal participation from all zones, if that can get them better net revenue. But that is not a reality. To get say 40 shortlisted candidates meeting their requirements, the channel has to audition 1000s of singers. It is much easier for the channels to get 1000 singers interested in participation from North that from south for the obvious reason. Holding audition in 1or 2 major cities in North can bring 1000s of hopefuls but to do the same in South, the channel has to hold auditions in all major cities in South (and still they may get so many interested) So more cost of production for them. And after doing all this they still will have less viewer ship from South and hence less revenue (sms votes). So why would they go out of the way to do something that is not in their commercial interest?