In a bowl, add arvi, water, salt, mix well & rest it for 30 minutes then strain & set aside.
In a wok,add cooking oil,cumin seeds & fry for 30 seconds.
Add onion, mix well and sauté until translucent.
Add ginger garlic paste and mix well.
Add tomatoes & mix well.
Add red chilli powder,salt,turmeric powder,mix well & cook for 2-3 minutes.
Add arvi & mix well.
Add water and mix well,cover & cook on medium low flame until tender (15-20 minutes) and keep mixing in between.
Add fennel seeds,coriander seeds,red chilli crushed & mix well.
Add water & mix well.
Add fresh coriander,cover & simmer on low flame for 2-3 minutes.
Add lemon juice & mix well. Garnish & serve!