Work on the extension of the Purple Line from Koreatown to Westwood has already started. But the Beverly Hills School District has been fighting it ever since plans were first introduced about six years ago. That’s because the Purple Line will run underneath Beverly Hills High School. The district says it’s worried about students breathing bad air from the construction work, and the possibility of an explosion from oil and gas pockets that sit underground. The district has filed four lawsuits to halt construction. There have been protests. And a lot of that activity is being funded by school bond money, which was supposed to be used to improve aging school facilities.