A monopoly is a firm that owns one hundred percent of the market. Since there are no competitors, the monopoly makes supernormal profits in the short and long run.
In India, monopolies are owned by the government. The IRCTC manages the railway network in India. On the other hand, HAL manufactures planes for the Indian military. Monopolies exist in industries that are capital intensive with multiple barriers to entry. For example, investors have to invest billions of dollars in the railway sector if they want to compete with IRCTC. Another barrier to entry is laws that make it difficult for private investors to enter the market.
A monopolistic competition market doesn’t have any barriers to entry. Investors can easily set up shop and start doing business. Examples of monopolistic competition companies are Ador Multiproducts and Dabur, which produce household items like detergents and sanitizers. Companies differentiate their products through packaging and brand name. There is also a lot of advertising in a monopolistic competition market. Ador and Dabur advertise their products everywhere. You’ll see their products on billboards, television, and newspapers.
In an oligopolistic market, more than two firms serve the market. Since the firms are few, they come together to control the price and supply of the commodity. This usually happens behind closed doors, because the government considers such behavior unethical. Since TATA Steel, JSW, and SAIL own the majority of the steel market, they have power over how its priced and distributed.