Exhaust gases from boilers ,vehicles,etc.,cause air pollution in cities.
Exhaust gases from boilers ,vehicles,etc.,cause air pollution in cities.
锅炉和车辆等排出的废气,污染城市空气.
Exhaust gases from boilers ,vehicles,etc.,cause air pollution in cities.
锅炉和车辆等排出的废气,污染城市空气.