1 Strain yogurt through a fine sieve for about 30 minutes.
2 Peel carrots, cut in half crosswise, then cut into very fine strips with a knife or peeler.
3 Peel the onions and cut into very thin strips.
4 Heat oil in a pan and toast the mustard seeds briefly until they begin to burst.
5 Add carrots and onions to pan. Add cumin, salt and chili powder and cook over medium heat for 3-4 minutes, stirring frequently until al dente.
6 Transfer mixture into a bowl and allow to cool.
7 Scoop yogurt into a bowl. Rinse mint and pat dry, chop leaves and add to yogurt. Squeeze lemon and stir juice to taste into yogurt.
8 Combine carrots with yogurt sauce and serve immediately.