Pakistani authorities issued a warning on Monday to pregnant women and elderly about the dangers posed by a sweltering heatwave sweeping the country, with temperatures soaring as high as 53 degrees Celsius. “Intensity, frequency and duration of the heatwaves in Pakistan is increasing as compared to previous years. Pregnant women, children and the elderly are the vulnerable,” Muhammad Saleem, spokesman for the climate change ministry, told dpa. On Sunday, the mercury in Mohenjo Daro, one of the world’s ancient major cities in Sindh province, was recorded at 53 degrees Celsius, according to the …