Wash the pumpkin. peel and chop the pumpkin. In a pressure cooker or pan heat oil. Add the fenugreek seeds and cumin seeds and fry for a minute on a low flame. Now add the red chilies and fry for some 15 seconds. Add the chopped pumpkin and all the dry spice powders except garam masala and dry mango powder. Add the sugar or jaggery. Mix the pumpkin with the rest of the spices and sugar/jaggery. Add water and salt. Cover the cooker with a lid and pressure cook for 7-8 minutes. If you do have a pressure cooker than cover the pan with a lid and cook the pumpkin for some 15-20 minutes till they become soft and mushy. Now mash the cooked and soft pumpkin with a spoon and add the garam masala and dry mango powder. Stir the mashed pumpkin well and cook for minute or two. If the sabzi still looks watery to you, then evaporate the water from the sabzi by cooking it without the lid. The sabzi should not be dry nor watery, just in between. Garnish with coriander leaves and serve hot.