When smoking is strictly prohibited in public places, bus, trains and similar other places, the newer invention of Vision Vivi Nova electronic cigarette is allowed in every place. The reason is that these kinds of cigarettes do not produce smoke, there is no need of burning tobacco and so harmful nicotine gas and other gases do not go outside.
http://dxtechinc.jimdo.com/2013/08/26/smoking-vision-vivi-nova-in-public-places-is-not-prohibited/