Geneva, June 16 (DPA) Around a quarter of global diseases and almost a quarter of all deaths are caused by environmental risks, says a new report by the World Health Organization (WHO).

It estimates that more than 13 million lives are lost every year due to avoidable causes and says a third of disease in children under the age of five can be attributed to environmental factors.

Tackling environmental risks could save up to four million lives a year, mainly in developing countries, according to the report.

Two of the biggest childhood killers, malaria and diarrhoeal diseases, could be significantly reduced, for example, by better water supply management and improved sanitation.

Measures targeting air pollution, as well as secondary smoking, could greatly reduce the 1.5 million deaths a year from respiratory infections. Better urban design would see a decline in fatal road accidents, the report says.

The report, it is claimed, breaks new ground in understanding the link between health and the environment.

"It brings together the best evidence available today on environmental links to health in 85 categories of disease and injury," said Maria Neira, of the WHO's Department for Public Health and Environment.

"We now have a hit list for problems we need to tackle most urgently in terms of health and the environment," she added.

The report says the right policies in sectors such as the environment, energy, transport and industry could prevent millions of unnecessary deaths every year.