Add 5 to 6 cups of water to a large pot. And bring it to boil and add salt.
To the pot, add pasta and a teaspoon of oil. Cook the pasta al dente according to the package instructions.
Drain pasta into a colander and keep it aside. You could pour some cool water over it to stop cooking further. Also, reserve some water in which pasta is cooked.
Meanwhile, while the pasta is boiling down, chop all the veggies.
Once you have boiled pasta and chopped veggies ready, heat a thick bottomed pan and add oil to it. Add chopped celery, garlic, and carrots. Let them fry for a couple of minutes.
Then add chopped zucchini and cook it for a minute or so.
Now add chopped bell peppers. Mix everything and let it fry for a couple of minutes on high flame. Here we don't want to cook veggies fully.
Then add red chili flakes, pepper powder, dried oregano, dried thyme, salt, and mix everything. As pasta already has salt, be cautious while adding salt.
Now add cooked pasta and toss everything. Cook for 4 to 5 minutes so that pasta absorbs all flavors. If it becomes too dry, you can add water reserved after draining the pasta.
Switch off the stove, and vegetable pasta is ready to serve!