How did it start?
After the Arab Spring uprising in 2011, President, Ali Abdullah Saleh handed over power to his deputy, Abdrabbuh Mansour Hadi. Hadi could not control the country well.
Who are the Houthis and which country is allegedly supporting them?
The Houthi movement of local Shias took advantage of the new president's weakness and occupied some areas and took over Sanaa.
Houthis have Iran's support.
How did Saudi Arabia get involved?
Yemen is a neighbour of saudi Arabia. Alarmed by the rise of a group they believed to be backed militarily by regional Shia power Iran, Saudi Arabia and eight other mostly Sunni Arab states began an air campaign aimed at restoring Mr Hadi's government.
Which country withdrew its forces from Yemen in August 2019?
UAE made a decision to withdraw the bulk of its forces from Yemen.
What role does the west have?
The coalition received logistical and intelligence support from the US, UK and France.
Are terrorist groups operating there?
Al-Qaeda in the Arabian Peninsula (AQAP) and the local affiliate of the rival Islamic State group (IS) have taken advantage of the chaos by seizing territory in the south and carrying out deadly attacks, notably in Aden.
Human cost?
Yemen is experiencing the world's worst man-made humanitarian disaster.
The UN says at least 7,025 civilians have been killed and 11,140 injured in the fighting since March 2015.Thousands more civilians have died from preventable causes, including malnutrition, disease and poor health.
About 80% of the population - 24 million people - need humanitarian assistance and protection.
About 20 million need help securing food, including almost 10 million who the UN says are just a step away from famine. Almost 240,000 of those people are facing "catastrophic levels of hunger".
More than 3 million people - including 2 million children - are acutely malnourished, which makes them more vulnerable to disease.