After onion is light brown, add in the pumpkin and potato, followed by turmeric, coriander powder, red chilli powder. Saute for 2 mins. Now add in some water, Once it boils, cover and cook until 3 whistles.Open the lid after some time. Add the garam masala, sugar, amchur and kasoori methi. Mix it all mash up some bits of pumpkin and garnish with coriander leaves. Let it simmer in low flame for 2 mintues. Sabji is ready.