Demand for necessary goods is inelastic.

When consumers buy about the same amount of commodity whether the price drops or falls, then the demand is called inelastic demand. For example demand for petrol for a cab driver is inelastic. Thus the demand for a commodity depends on the nature of Commodities, Commodities may be either necessaries or, luxuries. Normally, elasticity of demand for necessaries is inelastic and for luxurious demand tends to the elastic.