Chewing khat is widespread in Yemen, but during Ramadan the mild stimulant helps Yemenis stay awake at night while they break their fast, pray and read from the Koran, and try to find some escape from the harsh realities of life in the war-ravaged country.

"When I chew khat, I feel the desire to worship and read the Koran. It makes me able to do so for many hours," Tawfiq al-Saafani, a 42- year-old calligrapher and billboard maker, tells Efe.

"It helps you keep going and not get bored," he said. "When I chew, I can worship for 7-9 hours."

The shrub's stimulating effects can boost concentration, alertness and energy and give people a heightened sense of awareness, like a milder, less intense version of cocaine or methamphetamines.

Some 90% of men and 73% of women in Yemen consume khat on a daily basis, according to the World Health Organisation.