2 million displaced in three-year war

> Yemen’s civil war has been going on for nearly three years. > A Saudi-led coalition intervened in the conflict in 2015 to roll back Iranian-aligned Houthis, and backed internationally recognised President Abd-Rabbu Mansour Hadi. > The Saudi-led coalition has intensified its air strikes against Houthi posts since Houthis killed former president Saleh on Dec 4. > Saudi Arabia and the United States say Tehran has provided the missiles the rebels have fired into the kingdom. > Soldiers say Apache attack helicopters could help in the war against Houthis. > Authorities plan to slowly squeeze Sanaa while trying to allow civilians a free passage.