Put the oil in a large, wide, preferably non-stick pan and set over medium-high heat. When very hot, put in the cumin seeds. About 10 seconds later, put in the nigella, fennel seeds, fenugreek seeds, peppercorns and whole red chillies. [You should be generous with the spices, pumpkin needs it. The number of chillies is up to you...] Stir once or twice quickly, then add the pumpkin. Stir for 1 minute. Cover, turn the heat to low and cook for 40-45 minutes or until the pumpkin is just tender, stirring now and then and replacing the cover each time.
Uncover and add the salt, sugar and amchoor or lemon juice. Stir gently mashing the pumpkin lightly so that you retain some texture. [I don't see the point of mashing the pumpkin, unless you want it to look like baby food]. Serve hot.
(The whole chillies and peppercorns should not be eaten [I absolutely agree wrt the chillies, but I enjoy the cooked peppercorns, they add a bit of a punch.]) Serves 4.