Raita or pachadi is a South Asian/Indian condiment based on yogurt (dahi) and used as a sauce or dip.
The yogurt is seasoned with coriander (cilantro), cumin, mint, cayenne pepper, and other herbs and spices.
Vegetables such as cucumber and onions are mixed in. The mixture is served chilled.

Raita has a cooling effect on the palate which makes it a good foil for spicy Indian dishes.

Southern Indian cuisine, such as that found in the Bangalore region, often uses finely chopped or diced carrots mixed with dahi yogurt.

Cucumber is not included in authentic versions of the dish, because Ayurvedic tradition considers a mixture of cucumber and yoghurt to be harmful to the body.

It could be considered similar to the Greek tzatziki.

How to make Raita, a series of videos.

Cucumber & Mint Raita Recipe (not from the video)

• 1 large unpeeled cucumber, halved, seeded, coarsely grated
• 2 cups plain whole-milk yogurt
• 1/4 cup (packed) chopped fresh mint
• 1 teaspoon ground cumin
• 1/4 teaspoon plus pinch of cayenne pepper
  
  

Wrap grated cucumber in kitchen towel and squeeze dry. Whisk yogurt, mint, cumin, and 1/4 teaspoon cayenne pepper in medium bowl to blend. Add cucumbers and toss to coat. Season raita to taste with salt and pepper. Cover and refrigerate at least 2 hours. (Can be prepared 1 day ahead. Keep refrigerated.) Sprinkle raita with pinch of cayenne pepper and serve.