In a small pan over medium-low heat, combine kashmiri chilli powder, garam masala, cumin, coriander and turmeric. Cook, stirring frequently, for about 2 minutes, until spices are fragrant.
Blend the ginger and garlic and make in to a paste. Add the above spices, ginger garlic paste with Greek yogurt, lime zest and juice, oil and salt.
With a very sharp knife, make 2 or 3 slashes in each drumstick.
Mix the drumsticks with the marinade. Cover and refrigerate for at least 1 hours.
Preheat the oven to 160 degree C
Arrange the chicken on a baking tray, leaving a bit of space between the pieces. Spoon any marinade left in the bowl evenly over the drumsticks.
Roast for 45 minutes, until the chicken is done. Sprinkle some chaat masala on top. Your tandoori chicken is ready to serve.