Wash properly and parboil arbi so that it is still hard. Peel it when cold. Cut slices lengthwise.
Pur a pan on gas, and add oil. When the oil is slightly heated, add carom seeds (ajwain) and slit green chillies. When the start to splutter, add arbi slices, and cook uncovered on low flame till done.
When the arbi is properly cooked, add the tempering and mix well. Switch off the gas.
Add lemon juice to it. Decorate with chopped coriander and serve hot with kuttu ki puri, or as snack with a cup of tea.