When creating SVG images, you should consider their intended application. For example, if you draw a 32x32 image and have a 3-pixel wide shape, downscaling it to 16x16 pixels produces a 1.5-pixel line that looks blurry. To avoid this, make sure you use even dimensions.
The figure below shows an image with 2-pixel grid cells:
You can use the following tools to create SVG images: