Peel ,wash and grate the radish.
Whisk the yogurt and add few tbsp of water if it is too thick.
Add grated radish, chopped green chilies, chopped fresh coriander, chopped walnuts and salt in the yogurt and mix well
Heat ghee or oil in a small pan and add cumin seds and mustard seeds and a whole red chili.
When seeds start to crackle ,remove the pan from the heat and add the red chili powder.
Pour the tempering over the curd and mix gently.
Garnish with some fresh coriander and crushed walnuts.
Serve chilled with any rice preparation or paratha or rotis.