India, Sept. 3 -- A punishing late-summer heatwave has gripped large swathes of the US, forcing regional authorities to issue severe heat warnings, activate emergency cooling protocols, and implement widespread closures of public facilities in cities from St. Louis to Baltimore.

Why are extreme heat warnings forcing facility closures?

In the Midwest, sustained high temperatures and dangerous heat indices reaching well into the triple digits have compelled municipal leadership and local institutions in Missouri to shut down outdoor venues and limit public programming.

US public health officials stressed that the unseasonal intensity of the heat poses immediate physiological risks, particularly because bodies have not acclimatised to pro...