Plague? Help pls

Looks like it might be Spider Mites, check the underside of the leaves for very small red dots they can be hard to see, an indicator is the small sting marks that's seen on the top of the leaves. Try using a Neem oil spray and put sticky cards all around your plants, if your growing in a tent or a room you need to sterilize it thoroughly because they hide in all the small crevices.