right now they r in initial stages so they run few ads(except for chs like utv stars hd, movies now hd, history hd and mtunes hd), later all hd chs will gather max revenue from ads. in india no ch can sustain on subscription fee as there is leakage in this model as well as people are not ready to pay more for ad free chs
wait and see within few months hbo hd cha will also air ads as this ad free premium model will not succeed in India as of now