April 4, 2017 (Tuesday)
Armed conflicts and attacks
- Syrian Civil War
- A toxic gas attack, allegedly by Syrian warplanes, kills at least 83 and injures many more in rebel-held Khan Shaykhun, Idlib. (The Globe and Mail) (NBC News)
- Battle of Mosul
- The United Nations announces expansion of civilian camps for people fleeing Mosul, following resumption of airstrikes on ISIL-held portions of the Iraqi city. (Reuters) (Arab News)
Disasters and accidents
- Tornadoes of 2017
- Robert Bentley, the Governor of Alabama, declares a state of emergency due to forecasts of storms with the threat of tornadoes during the day. The neighboring state of Georgia also faces the threat of severe weather. (Fox News)
- 2017 Batangas earthquakes
- A magnitude 5.5 earthquake hits Batangas, causing damage to buildings and are felts as far as Metro Manila and Bulacan. (The Philippine Star) (Philippine Daily Inquirer)
Law and crime
- LGBT rights in the United States
- The full 7th U.S. Circuit Court of Appeals in Chicago rules (8-3) that the 1964 Civil Rights Act protects LGBT employees from workplace discrimination. (AP) (USA Today)
Science and technology
- Bertha, once the world's largest tunnel boring machine, completes its 9,270-foot-long (2,830 m) tunnel under Seattle, Washington, after four years of digging and a lengthy delay near the beginning of the project. (Wired)
- The National Assembly of Hungary passes a bill that undermines the functioning of the Central European University (CEU). Academics and academic institutions worldwide have expressed support for CEU. (BBC)
- English computer scientist Sir Timothy John Berners-Lee is awarded the 2016 A.M. Turing Award for inventing the World Wide Web, the first web browser, and the protocols and algorithms that allow the Web to scale. (Association for Computing Machinery)