Pork In Spinach Sauce

• 4 garlic (cloves crushed)
• 2 tomatoes (peeled)
• 2 green chiles seeded
• 1 ginger root (grated)
• 1 bay leaf
• 400 ml water
• 400 gr pork sirloin (boneless)
• 160 ml nonfat yogurt
• 45 ml vegetable oil
• 28 gr garam masala