The productivity of workers in extreme heat drops by two to three per cent for every degree above an ambient temperature of 20 degrees Celsius, highlights a report brought out by the United Nations' health and climate agencies.

Analysing evidence from studies from past five decades that "have provided conclusive evidence that workplace heat stress directly threatens workers' ability to live healthy and productive lives", the World Health Organization (WHO) and World Meteorological Organization (WMO) have also outlined guidance on how the growing risks of heat can be mitigated in the section of society.

Extreme heat events around the world occur more often and have become intense, increasing risks for both outdoor and indoor workers, authors of the report say, adding that related health risks include heatstroke and dehydration, and brain and kidney disorders.