Its hard to say with the information provided but it looks like a Toxic salt build up due to over-fertilization, the salt in the soil in blocking the roots from taking in nutrients resulting in that multi nutrient/micro nutrient deficient look or maybe it hasn't been fertilized at all and is in need of a standard n-p-k and a micro-nutrient. It also looks thirsty. Defiantly leech the soil and begin a fertilizer and micronutrient regiment. P.S Add as much info as you can for us to help you from what kind of fert you use and how often to what kind of oscilating fan you have (exaggeration but you get the point!)