Cut all karela in round shape(maximum 1/2 cms thick). Cut the Potato in lengthwise (2 inch long). Slice the onions and chop the tomatoes.
Now marinade the karelas with 1/2 tsp of turmeric n little bit salt. Take pan and deep fry the karela till light golden brown.Then,fry the potatoes till light golden brown.
Now take a pan heat some oil and saute the sliced onions till golden brown then add chopped green chilli,tomatoes,turmeric,Kashmiri red chilli powder,salt,sugar,1/2 cup water and cook till all masalas cooked properly and oil comes out.Then add fried potatoes and karela mix it well.Cook it for 10-15 minutes on medium flame.Check the seasoning and serve hot with steamed rice.