LISBON/MILAN (Reuters) – America’s decision to scrap rules designed to ensure a free and open internet leaves the European Union as the biggest market where Net neutrality still prevails — but critics say the EU is not a level playing field.

Consumer rights groups complain that EU regulations are being interpreted in ways that allow telecom firms and internet providers to offer discriminatory access to applications ranging from social media to music and video streaming.

“In practice, providers are allowed to use their position as gate-keepers to favor certain services, which is detrimental to consumers, competition and innovation as far as new, smaller players are concerned,” said Eduardo Santos, director of the D3 Association for the Defense of Digital Rights in Portugal.

“The law is lax on that, which is wrong,” he said.

At the heart of the issue is a practice whereby network operators charge nothing for data traffic on a popular app or a pool of apps in order to attract more clients.

This preferential pricing strategy, called “zero rating”, is being tolerated to an extent by European net neutrality rules.

In Portugal, the practice grabbed international attention when U.S. House representative Ro Khanna, campaigning against the removal of net neutrality in the United States, portrayed it as a country without a level playing field.

Khanna tweeted that Portuguese internet providers were “starting to split the net into packages” and cited offers advertised by local telecoms provider MEO, a unit of Dutch-listed Altice.

Aside from standard zero-rating pricing, some of MEO’s mobile phone…