One thing i have always noticed is that star channels often see the biggest drop during IPL seasons while zee channels hardly see any decline. I wonder if it has something to do with IPL being telecast on star sports so viewers who subscribe to the star pack probably shift to star sports during IPL, whereas viewers of other channels remain stable.
In fact, this year zee shows even saw growth during IPL. That vasudha show is topping the charts and its trps have increased whereas star shows fell from around 2.1-2.3 to 1.5-1.7. Most zee shows are actually much more stable compared to star shows.