Heat the oil in a large, heavy-based pan over medium heat, add the cumin, asafoetida, and fenugreek seeds, and stir-fry for about 1 minute, or until the seeds start to splutter.
Now add the tomatoes and fry for about 2-3 minutes. When they are half done, add the radishes, sugar, and the rest of the spices and the fresh ginger, then season with salt.
Cover and cook for about 15 minutes, or until the radishes become soft, adding a little water if necessary.