Cut stalks of celery and carrots into small cube size. Heat oil in a pan. When the oil is hot, add mustard seeds. Allow them to splutter. Add fenugreek seeds. Take care they don't turn black. Add curry leaves, red chillies.
Add the celery and carrot. Fry for some time. Add salt. Close the pan with lid.
While the vegetables are getting cooked, grind the remaining ingredients (except curd/yogurt) to a smooth paste in a blender. Once the vegetables are cooked, add the ground paste. Stir well immediately. Check for consistency. If too thick, add 1/2 cup of water. Boil for 1-2 seconds.
Remove from heat. Add curds/yogurt to make the dish into semi-liquid consistency.