Empty the potato chips into a large bowl.
Heat the vegetable oil in a small pot over medium heat.
Add the chili, curry leaves, fennel seeds, coriander seeds, cloves, and mustard seeds.
Swirl to coat, cover, and cook until the mustard seeds have stopped popping, about 2 minutes.
Remove from the heat and add the turmeric, chili powder, salt, and citric acid, if using.
Stir to combine and pour over the chips.
Sprinkle with the sugar and toss vigorously to coat the chips in the spiced oil and chilis.
Taste and add more salt, sugar, and/or citric acid to your preference.
Let stand until completely cooled and the chips have absorbed the oil, about 15 minutes.
Store in an airtight bag or container for up to 1 month.
