What industries are oligopolistic?

The most significant attributes of the oligopolistic market are:

(1) An industry ruled by a few huge firms,

(2) Firms sell either indistinguishable or separated items,

(3) The business has significant barriers to entry,

(4) The opponent firms stay constantly watchful about the moves of the firm which steps up and makes strategy changes. Eg. Advertisement.

Basic Industries which are oligopolistic in nature are Digital Television Services, Entertainment (Music and Film), Aircraft, Pharmaceuticals, PCs and Software, Phone Services, Advanced mobile phone and Computer Operating Systems, Aluminum and Steel , Oil and Gas and Vehicles