Shrimp Tikka with Fresh Mango Chutney

1/4 cup vegetable oil

2 tablespoons fresh lime juice

1 (1-inch) piece fresh jalapeño, chopped (about 2 teaspoons)

1 (1-inch) piece peeled ginger , chopped

1 large garlic clove, smashed

2 teaspoons ground garam masala

3/4 teaspoons turmeric

teaspoons grated nutmeg

2 pound large shrimp in shell, peeled, leaving tail fan attached For chutney:

1 teaspoon ground cumin

1 ( 3/4-pound) unripe mango , chopped

1/3 seedless cucumber , peeled and chopped ( 3/4 cup)

1/2 cup chopped red onion

1 to 2 teaspoons minced fresh jalapeño with seeds

3 tablespoons fresh lime juice

3 tablespoons thinly sliced mint

3 tablespoons chopped cilantro

10 (12-inch) wooden skewers, soaked in water

30 minutes

Accompaniment: lime wedges