The ruling is crucial since it may reshape the way Americans get information online which has been dominated by Google so far.

“After having carefully considered and weighed the witness testimony and evidence, the court reaches the following conclusion: Google is a monopolist, and it has acted as one to maintain its monopoly,” US District Judge Amit Mehta wrote in Monday’s opinion as quoted by CNN. “It has violated Section 2 of the Sherman Act.”

It is still not clear what penalties Google or Alphabet will face following the decision.

In 2020, the Justice Department filed a civil antitrust suit against Google for monopolizing search and search advertising, which are different markets from the digital advertising technology markets.

US Attorney General Merrick Garland, the country's top prosecutor, appreciated the ruling and said: " This victory against Google is an historic win for the American people."

"No company — no matter how large or influential — is above the law. The Justice Department will continue to vigorously enforce our antitrust laws,"Garland said.

He said: "This landmark decision holds Google accountable."

Meanwhile, Alphabet plans to appeal against the ruling of the US judge.

“This decision recognises that Google offers the best search engine, but concludes that we shouldn’t be allowed to make it easily available," the company said in a statement as quoted by BBC.

What is Anti anti-trust law?

The Antitrust Division enforces federal antitrust and competition laws.

"These laws prohibit anticompetitive conduct and mergers that deprive American consumers, taxpayers, and workers of the benefits of competition," US Department of Justice website said.