Amid India’s intense heatwave, how can wet-bulb temperature capture stress on human body?

Wet-bulb temperature captures combined effect of heat and humidity on the human body, indicating how effectively the body can cool itself through sweating. For example, a 45°C day in dry Rajasthan allows sweat to evaporate and the body to cope. But 38°C in humid Kolkata can be more lethal as the body overheats because sweat can't evaporate due to humidity.