Kitchen Sink Leakage from dishwasher drain outlet

Hi,
My kitchen sink has an outlet next to the tap that drains water from dishwasher.I am not sure what it is called.Lately water is overflowing from this outlet when my dishwasher drains the water out.I know previously the water would not overflow from the top but would direcly flow into the sink pipe.

Can you please help? how do I fix this?

Thanks.

 

How well does your sink drain?
I think it only does that when you have a glogged or slow drain.

 

The hose from the air gap down to the disposer may be clogged or kinked. This would restrict flow and cause a backup out of the airgap.