Heat 1 tbsp oil in large non-stick frying pan and cook the onion until soft and lightly coloured. Add the garlic, ginger and chilli and cook for 2 minutes more. Sprinkle the spices over and fry for a minute.
Stir in the lemon juice and chicken and cook for 2 minutes.
Pour the tomatoes into the pan, add 150ml water, a pinch of salt and sugar (or 3/4 tsp salt to get a spicy flavour and avoid sugar) and bring to a simmer.
Cook for 15 minutes / until done and well cooked, stirring occasionally. Serve with steamed basmati rice or Indian flat breads (chapatti / phulka ).