SVG does not always look sharp in HTML
I have an SVG icon made with Inkscape. The page size is width: 200px, height: 200px and the line size is width: 170px, height: 170px.
When I put it in a HTML page:
It is the same SVG it only changes the HTML. When the width is 30px it looks ok, When it is 35px it looks bad, When it is 40px it looks well, 35, 36, 37 and 39 has the same aspect
Why does it happen?