Oil industry is 'peddling misinformation' about electric vehicles - Electric vehicles are cleaner and more efficient than conventional vehicles. Reports against EVs are coming from oil-backed studies, leading to skewed public perceptions of battery-run autos.

Well they are greener - there is no question about that.
Question is how much.

They have a upfront cost due to batteries - mining/manufacturing lithium cells.

Power comes from various sources - but even coal is greener than disel or gasoline (much better filtering systems in place in a large scale powerplant than that small catalyzer in a car).

Then there is also the potential damage from old electric cars in the future if proper recycling is not in place.
A ICE is just a chunk of metal for the most part, Electric has batteries with a much bigger environmental impact.

Battery tech is holding electric back. And i wouldn't be amazed if oil is slowing battery tech progress (buying up startups/new technologies etc).

/r/Futurology Thread Link - cnbc.com