Manila, Philippines ? The World Health Organization called on governments Thursday to improve air quality in their cities, saying air pollution prematurely kills 2 million people a year, with more than half the deaths in developing countries.

Reducing pollution from particles that are too small to be filtered in the nose and throat and settle in the lungs could save as many as 300,000 lives every year, according to a statement issued by the WHO’s regional office in Manila.

Reducing levels of those extremely small particles – caused primarily by the burning of fossil and other types of fuel – could cut the deaths from air pollution by about 15 percent, said Maria Neira, the WHO director for public health and the environment.

It also could cut the global burden of disease from respiratory infections, heart disease and lung cancer, she said.