Grilled Tandoori Fish and Chips

In a large bowl, whisk together yogurt, garlic paste, ginger, paprika, curry powder, chili powder, cumin, and salt. Remove 1 cup of the mixture to a bowl and reserve for serving. Place fillets in a shallow dish and brush with remaining yogurt mixture to coat completely. Cover and refrigerate 1 hour. Chips: Place yam wedges skin side down on a large microwave-safe plate; cover with vented plastic wrap. Microwave on high 3 1/2 to 4 minutes, or until almost tender; let cool. Heat an outdoor gas grill, or prepare coals for a charcoal grill for direct grilling over medium-high heat. Mix ghee, garam masala, salt, and pepper in a large bowl; add yam wedges and gently toss to coat. Remove fillets from marinade; wipe off excess marinade. Brush the cooking grates clean and oil the grill rack. Lightly brush fillets with oil. Grill fillets and yams (keeping the grill lid closed as much as possible) until fish is opaque and still moist and yams are lightly charred, 6 to 8 minutes, carefully turning fillets once when fish releases easily from grill pan, and turning yam wedges as they brown. Serve with remaining yogurt mixture.