Place yoghurt, water, onion, tomato, cucumber and coriander in a large bowl. Add salt, pepper and sugar. Mix well. Chill in the fridge for at least 1-2 hours before serving. Will keep in the fridge for up to 3 days.
Toast cumin seeds in a hot, dry pan on medium heat for a few seconds until they start to turn a shade darker and crackle. Remove from heat. Add to the raita just before serving.
Yoghurt - Use the thickest full-fat yoghurt you can find. Make sure your yoghurt is unsweetened. Buffalo yoghurt, sheep's yoghurt or goat's yoghurt works really well too because they all have a beautiful tang.
Make It Vegan - by subbing regular yoghurt with unsweetened coconut yoghurt.
Garnish - Elevate flavour by sprinkling a pinch of ground cumin and ground chilli to your finished raita before serving.