It Looks likes a major search algorithm update today by Google.
So many webmasters in Search Communities talking about the update and traffic change on 1 August 2018, and now it is also confirmed by Google.
Google has also officially confirmed the update saying that is a major search update which they do several times in a year.
Check the official tweet by Google.
Each day, Google usually releases one or more changes designed to improve our results. Some are focused around specific improvements. Some are broad changes. Last week, we released a broad core algorithm update. We do these routinely several times per year….
— Google SearchLiaison (@searchliaison) March 12, 2018