Nuclear testing: Pakistan responds to a series of nuclear tests by India with five of its own codenamed Chagai-I, prompting the United States, Japan, and other nations to impose economic sanctions. Pakistan celebrates Youm-e-Takbir annually.

Nuclear weapons tests are experiments carried out to determine the performance of nuclear weapons and the effects of their explosion. Over 2,000 nuclear weapons tests have been carried out since 1945. Nuclear testing is a sensitive political issue. Governments have often performed tests to signal strength. Because of their destruction and fallout, testing has seen opposition by civilians as well as governments, with international bans having been agreed on. Thousands of tests have been performed, with most in the second half of the 20th century.

Chagai-I is the code name of five simultaneous underground nuclear tests conducted by Pakistan at 15:15 hrs PKT on 28 May 1998. The tests were performed at Ras Koh Hills in the Chagai District of Balochistan Province.

Economic sanctions or embargoes are commercial and financial penalties applied by states or institutions against states, groups, or individuals. Economic sanctions are a form of coercion that attempts to get an actor to change its behavior through disruption in economic exchange. Sanctions can be intended to compel or deter.

Youm-e-Takbir is celebrated as a national day in Pakistan on 28 May in commemoration of Chagai-I and Chagai-II series of nuclear tests. The nuclear tests made Pakistan the seventh nation to possess nuclear weapons and the first in the Muslim world.