The wavelength of light does not decrease as we approach a light source. The wavelength of light is a characteristic property of the light itself and remains constant regardless of the observer's position.
What may change as we approach a light source is the perceived intensity or brightness of the light. This change in intensity occurs because the total amount of light energy passing through a given area (such as the observer's eye or a light detector) increases as the observer moves closer to the source. This increase in energy can make the light appear brighter.
However, it's important to note that the wavelength of light, which determines its color, remains the same regardless of the observer's position. The color of light is determined by its wavelength, and as long as the light source itself does not change, the wavelength of the light remains constant.