The impact of fine particulate matter (PM2.5) highlighted by the World Health Organisation (WHO) study is felt through a broad spectrum of acute and chronic illnesses that cause premature death.

These include lung cancer, chronic obstructive pulmonary disease (COPD) and cardiovascular diseases. Worldwide, it is estimated to cause about 16 per cent of lung cancer deaths, 11 per cent of COPD deaths, and more than 20 per cent of ischaemic heart disease and stroke. Particulate matter pollution is an environmental health problem that affects people worldwide, but low- and middle-income countries disproportionately experience the burden.

A WHO South East Asian Region (SEAR) statement said, “Air pollution is the world’s biggest environmental risk to health and must be addressed on a priority basis as it continues to rise, causing long lasting disease and illness.”

The study findings, based on data derived from satellite measurements, air transport models and ground station monitors for more than 3000 locations, both rural and urban, were developed by WHO in collaboration with the University of Bath in UK.

Urban nightmare

While all regions of the world are affected, populations in low-income cities are the most impacted. Overall, 98 per cent of cities in low- and middle income countries with more than 100,000 inhabitants do not meet WHO air quality guidelines. However, in high-income countries, that percentage decreases to 56 per cent.

Earlier this year too, the WHO had warned that nearly 1.4 million Indians may have succumbed to diseases caused by indoor air pollution. The numbers released on Tuesday were specific to outdoor air pollution.

Of all of pollutants, fine particulate matter has the greatest impact on health. A lot of the fine particulate matter comes from fuel combustion, both from mobile sources such as vehicles and from stationary sources such as power plants, industry, households or biomass burning.