Heat oil in a large skillet over medium heat. Add cumin seeds and mustard seeds; cook and stir until browned, about 1 minute. Add onion; cook and stir until golden, about 6 minutes. Stir in coriander, ginger-garlic paste, and chile powder; cook until fragrant, about 1 minute.
Stir tomatoes into the skillet. Cover and cook until softened, 5 to 10 minutes. Pour in water; bring to a boil. Add eggs; cook until flavors combine, about 2 minutes. Season curry with salt and remove from heat.