Soak the kala chana for 3-4 hours or overnight and then drain out the water and wash it nicely. Peel the ridge gourd, wash it and cut it into big pieces. Sliced the onions and also cut the green chilli into small pieces.
Heat oil in a kadhai, add cumin seeds and green chilli to it, saute it and then add soaked kala chana to it, cook it for 2 minute and then add sliced ridge gourd into it, mix it well.
Add turmeric powder and salt into it. Mix it and cover the kadhai with a lid and cook it on low flame for 15 min by stirring occasionally.
As the ridge gourd and chana cook well and ridge gourd releases too much water, then cook it on high flame for 10 minutes by stirring occasionally so that its gravy become thick and it gets little dry. Then switch off the flame and serve it.