With a pestle and mortar crush cumin, coriander seeds, mustard seeds and fennel seeds. Roughly chop tomatoes, and grate the radishes.
Heat oil in a pot on a high. Once oil is hot, add curry leaves and freshly ground spices. Turn heat down heat to medium. Allow spices to sizzle.
Add chopped chillies before putting in tomatoes, finely chopped garlic, radishes, sugar and white wine vinegar into pot. Season with salt and pepper, adding more depending on your preference. Simmer on a medium-low heat until water evaporates, stirring occasionally.
Once the consistency has thickened, take off heat. Ladle into sanitised jars – sealing the lid by standing full jar upside down for an hour or two.
Note: If you would like a chunkier consistency, roughly chop the radishes instead of grating them.