Whatever it was, it was something that wasn't present when the English visited Australia in late 2006.
Anyway, it seems like the Indians are using the same balls that the English used and there is speculation that this is what has given them the winning edge.
Personally I think it's no excuse for Australia not to be able to play reverse swing, they should be able to use tennis balls with duct tape on one side for all I care, I don't see how a powerful cricket nation like Australia can't deal with reverse swing.
From my point of view, the only way a specific cricket ball was a factor in our Ashes loss was when Glenn McGrath stepped on one during training before the second test and injured himself.
That's what lost us the Ashes.
The only way a specific cricket ball will lose us the series in India this time around, is if they put one in the hands of Jason Krejza.
Thankfully, we've dodged that bullet - for now.

