Heat the vegetable oil in a large pan over medium heat. Add the cumin seeds, fennel seeds, nigella seeds, mustard seeds, and fenugreek seeds. Cook until the seeds begin to crackle.

Add the finely chopped onion and sauté until golden brown.

Stir in the garlic paste and ginger paste, cooking for an additional 2 minutes.

Add the slit green chillies, ground coriander, ground turmeric, and red chilli powder. Stir well to combine.

Add the chopped tomatoes and cook until they soften and the oil starts to separate from the mixture.

Add the chicken pieces to the pan, stirring to coat them with the spice mixture. Cook for 5-7 minutes until the chicken is no longer pink.

Pour in the water, add the salt, and bring the mixture to a boil. Reduce the heat, cover, and let it simmer for 20-25 minutes, or until the chicken is cooked through and tender.

Stir in the lemon juice and chopped fresh coriander before serving.