Judicial review is the power of judiciary to review the legality of a law passed by legislative body or an act by executive/administrative body. This power differs from country to country. In UK, judiciary can only interpret the Constitution but cannot invalidate/strike-down a law passed by a parliament, because most of the part of their Constitution is un-written. In Pakistan, India and USA, judiciary can strike-down a legislative law, if it contradicts with the Constitution.
In Pakistan, Supreme Court and Hight Courts can take judicial review under Article 184(3) and 199 of the Constitution 1973, respectively.
Initially it was started in England on the concept of ultra vires, which means that if any exercise by public office holders violates the Constitution, it could be questioned by judiciary. Marbury vs Madison is a famous case, which established the tradition that court can strike down a law contrary to the Constitution.
Pakistan's Constitution is a mix-up of both of the Constitutions of USA and UK. In Pakistan, judicial review powers were incorporated since the Constitution of 1962, under Article 98 and the same was transferred to the Constitution of 1973, under Article 199.
Article 199 says that if a HC maintains that there is no legal remedy for an aggrieved person/party available in the law, then HC can issue an order under the territorial jurisdiction of court, directing a person to obey law and not to act contradictory to the law. HC can also order to present a person brought before court, if court maintains that the specific person is under custody without legal authority.
Article 199 empowers HC with certain writs without using their technical name;
Writ of Mandamus: is issued when a public office holder violets the duties, assigned to that post.
Writ of Prohibition: is issued to tribunals/lower-courts to not to interfere in a case having appeal pending at apex court.
Writ of Certiorari: is issued when an inferior court acts without jurisdiction or the party is not given chance of right to hearing. Hence, superior court can seek review of a decision by inferior court.
Writ of Quo Warranto: is issued to review the legal right of a person to hold a public office.
Writ of Habeas Corpus: is issued to a person to prove the legality to keep a person under custody.