With the rise of GPS enabled smart phones, Google started providing more results based on the current user location.
Local SEO is a process for optimizing a website so that it ranks in the “Google Local Listings Map Pack”, a special featured “box” of websites that are in close geographical proximity to the searcher and are related to the search query’s intent. This box is displayed at the top of the page, even before the organic results (the natural results/websites that are shown based on relevance to the search query).
If you rank there, it’s highly possible you’ll get more traffic than the website which is currently at the no. 1 organic position.