In the hottest parts of the world, high temperatures and humidity will, for longer stretches, surpass a threshold that even young and healthy people could struggle to survive as the planet warms, study says
The paper is here
Figure 1 shows the locations:
Annual hot-hours under (A) 1.5, (B) 2, (C) 3, and (D) 4 °C of warming relative to preindustrial level
I think the brightly colored area may be the comparatively lower land just south of the Himalaya. The mountains can act as a backstop that allows heat and pollution to build up to intolerable levels while the air is not able to easily mix with cleaner and cooler air to the north.