New Delhi, May 15 -- Around 25% of all FIFA World Cup games are likely to be played in conditions of 26degC Wet Bulb Globe Temperature (WBGT) or higher - a heat index that includes temperature and humidity, a new analysis has said. About 5 games are expected to occur when the WBGT is 28degC or above (equivalent to about 38degC in dry heat, or 30degC in high humidity), a level that the global players' union FIFPRO (International Federation of Professional Footballers) considers to be unsafe for play and advises postponement. Wet-bulb temperature combines heat and humidity measurements to indicate how effectively the human body can cool itself through sweating when outdoors. A wet bulb temperature of 31 to 35 degree C can be fatal to humans d...