In a small bowl, combine the onion, garlic yogurt, lemon zest, lemon juice, salt, pepper, paprika, cinnamon, cloves, turmeric, ginger, cumin and cilantro. Mix together very well.
Place the tenderloin in a shallow dish or in a gallon size resealable bag. Add the marinade to the pork and spread it over the meat. Cover and refrigerate 8 hours or overnight.
MAKE THE RAITA
In a small bowl, combine the yogurt, cucumber, mint, cilantro and cumin. Stir well, cover and refrigerate until ready to use. (Can be made several hours ahead of time.)