Place apples and water in a large saucepan. Bring to a boil, reduce heat, and cook until apples are tender, stirring occasionally, about 25 minutes. Add more water as necessary to keep apples simmering.

Add tomatoes, onions, vinegar, sugar, raisins, curry, salt, mustard seeds, cayenne, and garlic to the saucepan. Stir until sugar dissolves.

Bring mixture to a boil. Reduce heat, and simmer until very thick, stirring occasionally, about 3 hours. Remove and discard mustard seed. Seal chutney in sterile containers.