Drain and put chana dal, toor dal, masoor dal, moong dal, ½ tsp turmeric powder, red chilli powder and salt in a pressure cooker.
Add 2 cups water and cook under pressure till 3 whistles are given out.
Meanwhile heat oil in a non stick pan. Slice onions and add and sauté. Slit green chillies.
Peel and cut white pumpkin into ½ inch pieces. Chop garlic.
When onions brown, add ginger paste and sauté for 2 minutes.
Break or cut dried red chillies into smaller pieces.
Add green chillies to the pan and sauté. Add pumpkin, salt and cover and cook till pumpkin is nearly done.
Open the cooker when the pressure reduces completely, add the dals to the pumpkin mixture and cook till pumpkin becomes soft.
Add tamarind pulp and remaining turmeric powder and mix well.
Heat ghee in a small non stick pan, add cumin seeds, garlic, red chillies and curry leaves, sauté for half a second, add to the dal and cover immediately to trap the flavours.Serve hot.