clean and cut chena/yam in to small cube size pieces.wash well and keep aside.
in a cooking vessel add chena/yam,salt ,chili powder and turmeric powder.add sufficient amount of water to cook chena.
cook chena well(do not over cook).switch off the stove and keep this aside.
heat oil in a pan splutter mustard seeds.then add curry leaves.saute well.then add chopped shallots and crushed garlic.saute till shallot become brown.then add chili pieces and fry it.