Increase and Decrease in Demand:

Now, if the other things, that is, determinants of demand other than price such as consumer’s tastes and preferences, income and prices of the related goods change, the whole demand curve will shift upward or downward. Increase in demand means that the consumer buys more of the good at various prices than before. For example, if the income of a consumer increases, or if the fashion improves, the consumer will buy greater quantities of the goods than before at various given prices. The consumer will buy OQ5 rather than OQ0 due to an upward shift or increase in demand (see Fig: Law of Demand). Similarly, the consumer will buy OQ4 instead of OQ0 due to a down shift or decrease in demand. This increase and decrease in demand happen due to the changes in factors other than the price of the commodity.

OQ0 – OQ4 -Decrease in demand

OQ0 – OQ5 -Increase in demand