Peel the skin and cut all the vegetables into 2 inch long piece.
Coarsely grind grated coconut, green chillies and cumin seeds. Keep it aside.
Method
Since each vegetable needs different time for cooking, I cooked cucumber, plantain and ash gourd together in a pan separately adding salt needed for that alone. When it is half cooked, add chopped raw mangoes.
Pressure cook the rest of the vegetables adding salt and turmeric powder for 2 whistles.You can cook in open pan also.The vegetables should be soft but not mushy. (use very less water and cook)
Add the grounded coconut paste and cook for a few minutes. Remove from flame.
Add curd and mix well. Check for salt. Season with coconut oil and curry leaves.