Google announced this week that what it has done in 2019 to combat Google Maps spam and violations. Google removed 4 million fake business profiles from Google My Business in 2019. It also removed 75 million policy-violating reviews from local profiles.
Back in 2016 we reported that Google Maps ads can and do show a purple ad label next to the local listings that are ads. But that has changed over the years and now Google is once again testing the purple ad label in the local ads, even on desktop.