Heat oil in a shallow pan, and add the urad dal and mustard seeds. When the seeds start to splutter, add the add green chillies, ginger, curry leaves, and onions, bell-peppers, and carrots, along with some salt.
Cover and cook for 3-4 minutes on low heat, stirring occasionally, until onions become translucent, and other vegetables are cooked.
Add the tomatoes and peas and saute for 2 minutes. Then add the water, and cover. When the water comes to a boil, add some more salt, cilantro leaves, and rasam powder, and vermicelli.
Cover and cook the vegetable vermicelli upma on low heat for 5-7 minutes, stirring occasionally. Remove the lid and cook for 2 more minutes until all the water evaporates.
Serve the vegetable vermicelli upma hot and either plain or with chutney powder or pickle of your choice.