Two women walk on a road as willow catkins drift in the air in Beijing, April 13, 2009. People are warned to wear veils or sunglasses while going outside during the season when catkins from willow and poplar trees float in the air, as they pose potential risks to the health of people's respiratory tract.
A cleaner sweeps woolly willow catkins to a roadside in Xuchang, central China's Henan province, April 13, 2009.
A man walks on the road as willow catkins fly in the air in a community in Beijing, April 13, 2009.
A couple covers their faces while walking as willow catkins are wafted by the wind in Beijing, April 13, 2009.
Two women cover their faces as they walk through a cloud of willow catkins on a street in Beijing, April 13, 2009.