Start by marinating your shrimp. Combine the chopped garlic, achaar, onion powder, chili powder, agave nectar, lemon juice, and shrimp.
Cover and marinate in the fridge for about a half-hour or so.
When you're ready to grill, thread the shrimp onto your skewers. Make sure the skewer goes through the shrimp in two places (at the top of the head and towards the bottom tail).
Fire up your grill and cook on both sides. Feel free to baste the shrimp with any left over marinade and/or butter and oil as they cook. The shrimp is done once it turns pink and curls into a C-shape.
Serve with grilled lemon wedges.