The acquisition of the S-400 air defence system by India from Russia is more strategically significant than the Modi government intends to publicly convey. It signifies a likely change in Indian strategy from the defence to the offensive. For all the talk beforehand of falling squadron strength in the Indian Air Force, which is a legitimate concern for the Indians (they are down to 31 squadrons of aircraft and urgently need at least 42 for a two-front war with China and Pakis