Abstract: Venturing outdoors may become deadly across wide swaths of India, Pakistan and Bangladesh by the end of the century as climate change drives heat and humidity to new extremes, according to a new study. These conditions could affect up to a third of the people living throughout the Indo-Gangetic Plain unless the global community ramps up efforts to rein in climate-warming carbon emissions. Today, that vast region is home to some 1.5 billion people. While most climate studies have been based on temperature projections, this one - published Wednesday in the journal Science Advances - is somewhat unique in also considering humidity as well as the body's ability to cool down in response. Most of those at risk in India, Pakistan and Bangladesh are poor farmworkers or outdoor construction laborers. They are unlikely to have air conditioners - up to 25 percent in of India's population still has no access to electricity. In some areas that have been deforested for industry or agriculture, they may not even have very much shade.