Yemen is a country of some 29 million persons, but over a third of them are at risk of starvation if Saudi and UAE bombing campaigns continue. Lise Grand, the United Nations coordinator for Yemen, has warned that the world has only 3 months to halt the slide toward catastrophe.
She seems to think that an immediate armistice must be called in the war to avoid this dire outcome. The Trump administration provides logistical and other help to the Saudi and UAE belligerents, and so the United States is embroiled in any human rights disaster there.
The Zaydi Shiite Houthi militia took control of the most populous parts of Yemen in 2014. Although the Zaydis are closer to Sunnism than other Shiites (such as the Twelvers of Iraq and Iran), the Wahhabis of Saudi Arabia hate them with a passion and have been trying for three decades to convert them to Wahhabism with their oil wealth. The Houthi revivalist movement arose in part as a reaction against that Wahhabi missionary drive and search for Saudi hegemony in Yemen.
The Saudis accuse the Houthis of being puppets of Iran, but that is a vast exaggeration. They are a largely indigenous movement.