This article is plain wrong. The original NZZ (Neue Zürcher Zeitung) article, which is linked in this article, says nowhere that the Tesla Model 3 was the best selling car in March. The Model 3 was only the fourth best selling car in March. You can find the original data here: https://www.auto.swiss/statistiken/autoverkaeufe-nach-modell...

According to the data the Škoda Octavia was sold nearly two times as much as the Model 3. It must be said, however, that the Model 3 is the best-selling electric car.