Google has launched first core update of 2025 and the first core update since December. And it will take up to 2 weeks to roll out completed. Google March 2025 Core Update is a significant, regular update by Google aimed at improving search algorithms to better surface relevant, satisfying content and incorporate more content from creators.

Google March 2025 Core Update means
Google March 2025 Core Update is the first core update of 2025, like a previous core update in December 2024. This update is part of Google search algorithms, it efforts to improve search results by better surfacing relevant and satisfying content from all types of sites. And this update would take up to two weeks to roll out completed as Google said.
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There isn’t a specific action website owners need to take in response to a core update unless they’ve seen a negative impact on their search rankings.
If there is dropping from position 2 to 4 then no need to worry about anything. But if website ranking dropping from position 4 to 29 it means large drop then you have to take action on content of your website.

For more details on Google core updates, you can read: Core Updates