Google Adsense is decade old utility. Back then, people mostly used desktops or laptops to surf the net. But with the huge surge of mobiles, game consoles, tablets and Smart TVs, internet accessibility has become much more. Under this scenario web designers are more inclined to design websites that are interface independent. It is called Responsive Web Design.
Advertisements have to be a part of this change.The Adsense allows a fixed width to the Ad tiles. But with the advent of responsive web design, this has proved to be a hindrance because a large ad tile may look good on a desktop screen but, if the same site is accessed from a mobile then the large Ad poses a problem while surfing.
But, this started a debate that using this code to alter the Ad size dynamically will be the violation of Adsense policies that prohibit alteration of Ad tiles size.
Michel Wester of a certain WebSonic.nl is a Adsense publisher in Netherlands contacted the Adsense team for a confirmation and given below is his reply which says that altering Ad tiles for interactive web designing is NOT a violation of policies.