Airtel has announced their new packs i.e. price range for 3G which starts from Rs 8 in Mumbai, Chennai, most of the Places in Chennai and costliest in Delhi for Rs 11. This package is of 10 Mb which is valid for just one day. The plans can be seen here by selecting a state and city. I am not sure why the starter pack is priced differently in different city.
The rates overall don’t differ much specially for high rated packs, FlexiShield is one such example and It still seems costly to me. Another interesting thing to notice when you compare pricing between cities, they differ only by a 1, 2 or three rupees. For example when you compare the Standard Pack between Mumbai and Chennai you will see the 450 pack in Mumbai is 450 which is 451 in Chennai, 61 Sachet pack in Mumbai costs 63 in Chennai.