The World Health Organisation (WHO) says the environment is killing millions of people every year.

Nearly one in four deaths are linked to unhealthy environments and are avoidable, according to a new WHO report.

The analysis found environmental risks contribute to over 100 of the most dangerous diseases on the planet.

The risks kill about 12.6 million people a year, or 23 per cent of all deaths.

Breaking it down even further, the WHO says two-thirds (8.2 million) of deaths are from non-communicable diseases (NCDs), such as strokes, cancers and heart illnesses.

This is a significant rise in the last 10 years, say the authors.

While deaths from infectious diseases have fallen since 2006, deaths from NCDs linked to indoor and outdoor air pollution, climate change and synthetic chemicals have increased.

The biggest global environmental killers are; strokes (2.5 million a year), heart disease (2.3 million), unintentional injuries (1.7 million), cancers linked to the environment (1.7 million), respiratory diseases (1.4 million), and diarrhoeal diseases (846,000).

“A healthy environment underpins a healthy population,” says Margaret Chan, WHO director general.

“If countries do not take actions to make environments where people live and work healthy, millions will continue to become ill and die too young.”

The deaths are often linked to poverty and rapid urbanisation, the report claims, and that indoor and outdoor air pollution are becoming increasing elements.

“Decreases in air quality have been observed in many low- and middle-income cities around the world in recent years. Increased exposure to air pollution will mainly increase NCDs, but also respiratory infections in children under five years,” says the report.

“Modern risks, like ambient air pollution and unsafe use of chemicals, tend to increase in countries undergoing rapid development, before control over such factors is improved when full transition to high-income societies is made.”

“Air pollution was associated with increased hospital admissions and deaths from stroke.

“The evidence for an association between stroke and both short-term and prolonged increased exposure to fine particles (PM2.5) is increasing. Also, short-term exposure to increased ozone levels was associated with stroke incidence. In 2012, 25 per cent of the global stroke burden was attributable to ambient air pollution,” it says.

“Total environmental deaths are unchanged since 2002, but show a strong shift to non-communicable diseases,” say the authors.

“The last decade has seen a shift away from infectious, parasitic and nutritional diseases, not only in terms of the environmental fraction but also the total burden.

“This shift is mainly due to a global decline of infectious disease rates, and a reduction in the environmental risks causing infectious diseases. A higher share of people have access to safe water and sanitation, and a lower share of households use solid fuels for cooking.

“Diarrhoeal diseases are one of the main contributors to global child mortality, causing 20 per cent of all deaths in children under five years. WHO recently estimated that 58 per cent of all cases of diarrhoea in low and middle income countries could be attributed to inadequate drinking-water (34 per cent), sanitation (19 per cent) and hygiene (20 per cent).

“Malaria is estimated to have caused 584,000 deaths in 2012, mostly among African children. About 42 per cent (28–55 per cent) of the global malaria burden could be prevented by environmental management,” the report says.

“Dengue fever is the most rapidly spreading mosquito-borne viral disease in the world. Rapid urbanisation, unreliable drinking water supply services, increased population mobility and global trade are important determinants of the resurgence of the disease.

But some of the greatest environmental risks come from activities that do not appear very dangerous.

Falling down is the second-highest cause of death from unintentional injuries, killing 690,000 people in 2012.

An additional 372,000 people drowned in 2012, making it the leading deadly ‘injury’ for children under five years.

Each year, there are 268,000 deaths due to burns from exposure to fire, heat or hot substances, 193,000 deaths from unintentional poisonings by chemicals or other noxious substances, including drugs, and toxic vapours and gases, lead poisoning from informal recycling or gold extraction, or from industrial emissions.

Road accidents are the single largest cause of death from injury, killing around 1.25 million deaths per year.

Almost half of all deaths on the road are motorcyclists, cyclists and pedestrians.

“There’s an urgent need for investment in strategies to reduce environmental risks in our cities, homes and workplaces,” said Dr Maria Neira, WHO director, department of public health, environmental and social determinants of health.

“Such investments can significantly reduce the rising worldwide burden of cardiovascular and respiratory diseases, injuries and cancers, and lead to immediate savings in healthcare costs.”

More details are available here.