In early June 2019, Google launched two updates to their algorithm. The major update was rolled out from June 3rd to June 8th which coincided with the diversity update rolled out from June 4 - June 6th.
Diversity update: Google wants to diversify the domains that are appearing in SERPs. i.e. for a search query, lets say "restaurants in mumbai", zomato.com would occupy 3-4 slots on the first page. With the diversity update only the strongest page for the search term would rank.
Core Algorithm update: The core algorithm update also led to fluctuations in rankings across many businesses. What experts say is that the core update devalued older pages on websites. For example, if you have 150 pages on your website, and 80% of these are not updated regularly, then they might loose ranking on SERPs and your traffic might drop.
How do you counter the drop in Organic traffic due to these updates. 1. First and foremost, you need to understand which pages on your websites have seen a drop in traffic. Just go to Search Console and go to the Search Analytics report. Click on Pages and then pull out a report for date comparison. Compare traffic before the algorithm updates (May 2019) to last 30 day traffic (post algorithm update). For all the pages, check the Avg. position and see which pages have a drop. Make a list of all pages that have seen a drop in traffic.
2. Now you need to work on these pages. Essentially, Google has devalued these pages as they are either old or because of the diversity update. If the page is old, then you need to refresh the content on the page and overall make the page stronger by adding different long tail keywords and sections to the pages. You can look at the keywords for which these pages are ranking (go to the queries tab in Search analytics) and then identify long tail variants (LSI) for the primary keyword. Include content related to these keywords / theme on the old page.
3. Getting leaner: As a website, you should always look at getting leaner i.e. getting rid of pages that have very less content / no content and do not show up in SERPs. So if you have 100 blogs and only 10 blogs are giving you all the traffic, either update the other 90 blogs to make them more comprehensive or get rid of blogs that cover the same subject / weak blogs. This way you will have lesser pages, but more stronger pages that are indexed by Google.