The distinction between pollution vs waste is subtle. However, there are ways to look at each to distinguish between the two. First, a quick look at the definitions:
From the definitions above, waste is fairly general, no connotation of negative consequences. For any processes in the universe, waste (byproducts) will always be created. For example, a byproduct of hydrocarbon combustion is carbon dioxide which is attributed to the greenhouse effect and global warming—clearly a negative example of waste. Water is another byproduct of combustion, that rarely has negative consequences, but it is waste. As a different example, oxygen is a waste product of photosynthesis, but humans and animals require it to breathe—clearly a positive example of waste. Waste depends on perspective. Growing levels of carbon dioxide are increasing the strength of the greenhouse effect, but some concentration of carbon dioxide is needed because plants need it to survive. However, the large amounts that humans release from fossil fuel use means that carbon dioxide has negative impacts.
Unlike waste, pollution always means that there are negative consequences. Pollution is defined as the harmful effects of an activity, which is the main difference between pollution and waste. All process create waste, but not all will create pollution. Since not all waste is harmful, not all waste is pollution. When waste is indeed harmful, it would then be classified as pollution.
Reducing waste often reduces environmental impact, either from the disposal, or from the creation in the first place. This leads to the popularity of alternative disposal methods—like compost, recycling or even reusing a product—rather than filling landfills.