The event loop is a crucial aspect of Node.js, as it enables asynchronous behavior. It's a programming construct that constantly waits for tasks, executes them, and then waits for more. This model is central to JavaScript's 'non-blocking' nature—ensuring that the Node.js doesn't wait for an operation to complete before moving on to the next one.
Thus, applications remain responsive and less resource-intensive, particularly useful when managing numerous concurrent operations.