Place a frying pan over medium heat and add the oil.
Once the oil is hot, add the black mustard seeds. Wait for them to pop and sizzle, which should only take a few seconds.
Immediately add the pineapple chunks and stir-fry for about 4 minutes, until the pineapple begins to soften and look translucent.
Stir in the sugar, lemon juice, turmeric, and chopped green chile.
Continue to cook for one more minute, allowing the flavors to meld.
Remove the pan from the heat and transfer the pineapple mixture to a mixing bowl to cool slightly.
Gently smash the cooked pineapple with the back of a fork. You want to break it down so it becomes juicy, but still retain some texture.
Add the Greek yogurt and salt to the bowl.
Stir everything together until well combined.
Taste the raita and adjust the sugar, salt, or lemon juice if needed to balance the flavors.
Serve chilled.
