European Union regulators approved Google's $3.1 billion takeover of ad firm DoubleClick, an online ad tracker on Wednesday, saying the deal will affect online advertising competition.

The Commission, the EU's top competition watchdog, said it found no proof that a merger between Google and DoubleClick would cause competitors to go out of business, according to Associate Press.

The commission said this is because Microsoft, Yahoo and AOL offered advertisers credible alternatives for placing ads online.

Privacy advocates have objected to the deal, saying it would give the two firms unprecedented access to information about consumers.

The deal combines internet search engine giant Google's dominance in pay-per-click web advertising with DoubleClick's market-leading position in flashier display ads.

For the past six years, the EU has never rejected a merger approved by US authorities.