Android back button really slow


I have an application with multiple scenes.

When I am going forward, i mean loading scene number 1 from number 0, all is well.

But when i try to load a previous scene, it takes a lot of time. How can i make it faster?

if (Input.GetKeyDown(KeyCode.Escape))

            // ON BACK PRESSED 

I am currently using Input.GetKeyDown in update method.

Try using SceneManager.LoadScene instead of Application.LoadLevel, make sure you are also using unity.SceneManagment;