This document discusses monopoly markets and their key features. A monopoly market is one where there is a single seller of a product or service without close substitutes. Examples given include railways in India, RTA buses, and the metro system in Dubai. Key features of a monopoly include there being one seller and many buyers, restrictions on new firms entering the market, a lack of close substitutes, and the monopolist having full control over price. The document also notes that monopolies can engage in price discrimination by charging different prices to different buyers for the same good or service.