Automobile service providers cautioned on Friday that a blocked EU plan to provide equitable access to valuable vehicle data might open the door to unfair competition from US and Chinese digital firms.

The battle over vehicle data between automakers and a combination of insurers, leasing firms, and repair shops highlights the enormous potential of the connected car industry, which Fortune Business Insights estimates may reach 250 billion-400 billion euros ($272 billion-$435 billion) by 2030.

Carmakers are looking to generate revenue from software products and subscription services driven by data which covers everything from driving habits to fuel consumption and tyre wear.

Data ownership, however, is not clearly defined in EU law, which has spawned the current dispute between carmakers and those who want to access it.

The European Commission had originally planned to adopt rules on how the data should be shared in the second quarter of the year, according to its agenda, but has yet to come up with a legislative proposal.

Car services groups are already concerned about the small number of players in the industry with access to the data, said Benjamin Krieger, secretary general of the European Association of Automotive Suppliers (CLEPA).

Unfair access could soon mean the sector “will be dominated by players from the United States and China”, he told reporters.

Another problem, which legislation could solve, is unstandardised data, said Laurianne Krid, director general of the Federation Internationale de l’Automobile, which promotes safety in motor sports.

Car makers in turn said the Commission’s proposed Data Act gives users control over data generated by vehicles, providing third parties fair and non-discriminatory access to the data.

Krieger said it does not address the specificities in the auto sector. “It does not reflect the technology and the competitive situation,” he said.

The Commission did not immediately respond to a request for comment.

Alphabet’s Google has already got a foothold in the market, picked by General Motors to develop infotainment systems for future electric vehicles as the U.S. carmaker phases out Apple CarPlay and Android Auto technologies.

Last month, Mercedes Benz teamed up with Google to offer traffic information and automatic rerouting in its cars.