Finely chop the onion and garlic, then the ginger and turmeric roots. Deseed the chilli and remove the veins with a knife, then chop the chilli flesh finely.
Heat the oil in a heavy-based pot and fry the onion for 5 minutes. Add the ginger, garlic, turmeric, chilli and cumin seeds.
Meanwhile, cut the papaya into small chunks. Coarsely grind the black peppercorns.
Add the papaya and peppercorn to the pan, then pour in the vinegar and add the sugar and salt. Stir, then bring to the boil. Reduce the heat and simmer for 20-30 minutes until you have a thick, sticky chutney, stirring occasionally.
Spoon the hot chutney into sterilized jars and seal.
When the jars cooled down completely, store them in a dark place.
When opened, store the jars in the refrigerator.