(i) Increase in income of its Consumer: The quantity of a good that the consumer demands can increase with the rise in income depending on the nature of the good.
(a) Normal goods: These are the goods for which the demand is directly related to consumer's income. Other things remaining constant, demand for these goods increases in response to increase in consumer's income. For example full cream milk, pulses, grains, etc.
When income increase, the demand curve D shifts to right to D1
(b) Inferior goods: These are the goods for which the demand is inversely related to consumer's income. Demand for these goods decreases in response to increase in income. For example coarse cereals, toned milk, etc. When income increases, the demand curve D shifts to left to D1
(ii) Rise in price of its Substitute goods: Substitute goods are those goods which can be used in place of one another for satisfaction of a particular want, like tea and coffee. Demand for a given commodity varies directly with the price of a substitute good. For example if price of a substitute good (say coffee) increases, then demand for given commodity (say tea) will rise as tea will become relatively cheaper in comparison to coffee.
