The World Health Organisation (WHO) said on Wednesday that mitigating climate change would save millions of lives at a global level.

According to WHO, exposure to pollution results in seven million deaths every year. The organisation says climate change affects a number of diseases such as asthma, chronic obstructive pulmonary diseases, lung cancer, stroke or ischemic heart diseases.

Speaking during COP24, United Nations talks on climate change in Katowice, Poland, WHO’s head of environmental determinants of health, Maria Neira said a number of pulmonary and heart diseases caused by pollution were not included in decision-making processes and documents related to climate change.

Diarmid Campbell-Lendrum, a team leader for climate change and health with WHO, added that health benefits of meeting the 2 Degree C Goal, which aims to cap a rise in average surface temperatures at 2 degrees Celsius (3.6 Fahrenheit), are approximately twice the value of what it would cost to implement that mitigation at the global level.

COP24 talks are billed as the most important U.N. conference since the landmark Paris 2015 deal on climate change.

Over the next two weeks, the aim is to make an end-of-year deadline for agreeing a rule book on how to enforce global action to limit further warming of the planet.