Main causes of increase in demand or rightward shift in demand of a commodity are as under:
(i) Income of the Consumer: With increase in income of the consumer, the demand curve for normal goods, shifts to the right.
(ii) Price of Related Goods: In case of substitute goods, demand for a commodity rises (or demand curve shifts to the right) with rise in price of the substitute commodity. In case of complementary goods, demand for the commodity rises with a fall in the price of complementary commodity.
(iii) Taste and Preferences: If consumer's tastes and preferences change in favour of the commodity, the quantity demanded of the commodity rises (and demand curve shifts to the right).
(iv) Expectations: If the consumer expects that price in the near future will rise, he will buy more quantity at the prevailing price and hence demand curve shifts to the right.
