Causes of a leftward shift in demand curve i.e. decrease in demand of a commodity are as follows:
(i) Rise in income in case of inferior goods When income of the consumer increases, he will decrease the consumption of inferior goods, e.g. a person decreases the consumption of dalda refined when his income increases.
(ii) Fall in income in case of normal goods When income of the consumer decreases, he will decrease the consumption of normal goods, e.g. a person decreases the consumption of pure ghee when his income decreases.
(iii) Fall in price of substitute goods In case of such goods,
decrease in the price of one causes decrease in the demand of other, e.g. tea or coffee. If the price of tea falls, consumer’s demand for coffee falls.
(iv) Rise in price of complementary goods In case of such goods, increase in the price of one causes decrease in the demand of other, e.g. car and petrol. If the price of petrol rises, consumer’s demand for cars will fall.