Image edges are distorted inside game

I dont know how to explain this, so I will use images to describe my problem.

The image I made using InkScape:

What it looks like in-game (ignore the runner):

As you can see the edges are not "sharp" ingame, even the static background (front-mountains and grass is scrolling) is distorted. I think you can see what I mean. What causes this? How can I fix it?

I use LibGdx to build my game, inside Android studio.

some relevant code:

background = new Sprite(new Texture(Gdx.files.internal("runner_background.png"))); camera = new OrthographicCamera(); viewport = new FitViewport(480, 800,camera); viewport.apply(); camera.position.set(camera.viewportWidth / 2f, camera.viewportHeight / 2f, 0); camera.update(); 

I draw my background like this, my RunnerScreen render method:

runnerWorld.update(delta); Gdx.gl.glClearColor(1, 1, 1, 1); Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); camera.update(); batch.setProjectionMatrix(camera.combined); batch.begin(); runnerWorld.render(batch); batch.end(); 

my runnerWorld render-method:

public void render(SpriteBatch batch){ batch.draw(background, 0 ,0); scroller.render(batch); runner.render(batch); }