Take oil in the pressure pan and add mustard seeds and cumin seeds to it and switch on the gas. Meanwhile crush the chopped onions, green chilli and garlic coarsely. Once the mustard seeds crackles add the crushed mixture to it and cook till onions becomes pinkish.

Now crush the chopped tomatoes into smooth paste and add it to the pan. Let the tomatoes cook till the oil starts separating.

Now add all the spices to the gravy. Mix it well and then add the green Tuvar and chopped purple yam to it.

Mix everything well and added required amount of water and mix well again. Close the pressure pan and cook for two whistles. Then simmer the flame and let it cook for 5-7 minutes and switch off the gas.

Once the pressure releases open the pan and the sabji is ready to serve.