Over a dozen resolutions, including new approaches to tackle air pollution, the single biggest environmental killer that claims 6.5 million lives each year, are on the table at the three-day third UN Environment Assembly that began here on Monday.

Studies indicate that over 80 per cent of cities don't meet UN health standards on air quality.

The new UN Environment report, titled "The Executive Director's Report: Towards a Pollution-Free Planet", which the meeting is using as the basis for defining the problems and laying out new action areas, recommended political leadership and partnerships at all levels and action on the worst pollutants.

It also favoured lifestyle changes, low-carbon tech investments and advocacy.

The recommendations are based on analysis of pollution in all its forms, including air, land, freshwater, marine, chemical and waste pollution.

Overall, environmental degradation causes nearly one in four of all deaths worldwide, or 12.6 million people a year, and the widespread destruction of key ecosystems, says the report.

Exposure to lead in paint, which causes brain damage to 600,000 children annually, and water and soil pollution are also key focus areas. Seas already contain 500 "dead zones" with too little oxygen to support marine life.

Painting a darker picture, the report says over 80 per cent of the world's wastewater is released into the environment without treatment, poisoning the fields and the lakes and rivers that provide drinking water to 300 million people.

There is also a huge economic cost.

A just-published report by the Lancet Commission on Pollution and Health says that welfare losses due to pollution are estimated at over $4.6 trillion each year, equivalent to 6.2 per cent of global economic output.

"Given the grim statistics on how we are poisoning ourselves and our planet, bold decisions from the UN Environment Assembly are critical," UN Environment head Erik Solheim said.

"The governments need to take actions. We are seeing actions but more actions need to step up immediately. The private sector needs to act. Also civil society," Solheim told IANS.

Edgar Gutierrez, Costa Rica's Minister of Environment and Energy and President of the 2017 assembly said: "Our collective goal must be to embrace ways to reduce pollution drastically."

"Focussing on the quality of growth is key for improvements in quality of life," said Ligia Noronha, Director of UN Environment's Economy Division.

"That requires a culture that supports responsible production and does not hold up unrestrained consumption as an aspirational way of life. We need to invest differently to transform our economies, also bringing in the private sector to back clean growth."

The UN Environment sees the participation of celebrity activists, such as UN Environment's new Goodwill Ambassador, English singer and songwriter Ellie Goulding.

Over 4,000 heads of state, ministers, business leaders, UN officials and civil society representatives gathered here to mull ways to tackle the global menace of pollution.