Have you done the mask yourself?Get a cylindrical kind of shape made out of your old T-shirt. Get a "naada" strip, as it is called, to get it firmly used as a mask. This Youtube video, in Hindi, is doing its rounds. Someone will get this done in other languages as well.
Now, is this the best? There are ready-mades sold by hundreds of tailors, who have found a new business thriving. They are not the exact cylindrical types, but they seem to serve a purpose. They do cover one's nose and are quite tight-fitting as well.
Have you made such a mask? Or are the ones made of cloth and sold in so many places, just about okay?