This repo is an example of how to find which polygon a point belongs to.
This could be more efficient if using an R-Tree to store the polygons, however was only intended as a proof of concept.
This is intended to find which ward a point belongs to in Udaipur, Rajasthan. But you could plug in your own KML file.
Please make sure you add your own Google Maps API key to the WardFinder.ejs file