SAN FRANCISCO (Reuters) - Websites and apps using Google’s advertising tools will be able to block personalized ads to internet users in California and elsewhere as part of the Alphabet Inc unit’s effort to help them comply with the state’s new privacy law, it told clients this week.

FILE PHOTO: The Google logo is pictured atop an office building in Irvine, California, U.S. August 7, 2017. REUTERS/Mike Blake

The California Consumer Privacy Act (CCPA), which goes into effect on Jan. 1, requires large businesses to let consumers opt out of the sale of their personal data. Lobbying by internet companies earlier this year failed to have the law exclude personalized ads, leaving the most popular and lucrative online ads in jeopardy.

Advertisers sometimes spend up to 10 times more money to place personalized ads, which take into account a consumer’s browsing history, interests and past behavior when determining which message to display.

It is unclear how many publisher and advertiser clients will enable the new restrictions, as interpretations of the law may vary. Google declined to elaborate on whether further measures related to the new law were forthcoming.

Websites and apps selling ads through Google tools such as AdSense and Ad Manager are not required to make significant changes under the company’s new compliance terms, which it posted online and sent to clients over the last three days.

But ad sellers can choose to stop personalized ads either to all consumers with internet addresses originating in California or to any individual worldwide that blocks the sale of personal data.

Google said that when the “restricted data processing” is triggered, ads will only be based off general data such as the user’s city-level location or the subject of the page where the ad is appearing.

Additionally, Google will not record personal information for future advertising purposes in the restricted mode.

Advertisers using Google’s tools also will have the choice to restrict data processing, though they would then lose features used to personalize ads to consumers that, for instance, have visited a particular store or installed a particular app.

The California law has been compared to Europe’s General Data Protection Regulation, a privacy law affecting European users that went into effect in 2018 and has become the basis of data privacy investigations targeting Google, Facebook Inc and other tech companies.