BBC: Scientists in India and Pakistan say higher temperatures were just one factor behind the recent heatwaves and other causes have yet to be established.
They say low air pressure, high humidity and an unusually absent wind played key roles in making the heat unbearable but they do not know why such conditions prevailed at this time of the year.
The temperature forecast for the heatwave peak in Karachi last week was 43C, according to meteorologists in Pakistan.
The prediction was accurate but...