In a large bowl, combine all the ingredients for the cauliflower - cauliflower florets, oil, garlic powder, cumin, salt and pepper. Toss until well combined.
Transfer the spiced cauliflower to the air fryer basket. Make sure they are spread in a single layer.
Set the air fryer at 380F for 15 minutes.
While the cauliflower is cooking, add all the sauce ingredients in a small blender or food processor - cilantro, yogurt, green chili pepper, garlic, cumin, salt and lime juice. Blend to a sauce. Add 1-2 tablespoons of water as needed to blend.
After the air fryer cooking time is done and the cauliflower is roasted, transfer to a serving plate. Drizzle the sauce over the cauliflower. Any leftover sauce can be used as a dip for the cauliflower. Serve right away!