Nearly a quarter of all deaths are linked to manageable environmental factors such as pollution, workplace hazards and sanitary infrastructure, the World Health Organization (WHO) said Tuesday.
An estimated 12.6 million people died from living or working in unhealthy environments in 2012, accounting for 23 per cent of global deaths, the UN health agency said in a report, citing the latest available data.
Some 4.8 million people die each year from cardiovascular problems that are caused by a broad range of environmental issues.
The best strategies to help prevent strokes and heart attacks are to avoid air pollution, smoking, exposure to lead, stressful working conditions and shift work, WHO said.
Preventable injuries including traffic accidents were next on the WHO's list of causes, with 1.7 million traffic deaths occurring every year.
WHO experts pointed out that poor urban planning contributes to many road accidents.
A further 1.7 million deaths from cancer are linked to factors such as air pollution, second-hand smoke, chemicals and excessive exposure to radiation and sunlight.
The UN health agency also urged countries to develop strategies to reduce the 1.4 million annual deaths from chronic respiratory diseases caused by unclean air and by exposure to dust and mold in workplaces and homes.
The WHO report also charted a decrease in infectious diseases.
Illnesses such as diarrhoea and malaria have declined as access to clean water, sanitation and medical services has improved in many countries.
"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," WHO Director General Margaret Chan said.
WHO found that the share of preventable deaths for children under five is 26 per cent, higher than the global average.