As for fasting, in regions where days or nights are extremely long or too short, for example over 18 hours, one should observe their fast according to the prayer times of those regions with normal day length. For instance, one should calculate how long fasting lasts in Tehran or Cairo and start fasting from fajr adhān according to the time in their own area and fast for the same number of hours. But as for prayer, in areas where days are not too short, one should perform prayers according to sunrise and sunset and midday of that area. And if days are too short, one should act in accordance with what we said in regards to fasting.